ORCID Profile
0000-0002-4976-4314
Current Organisation
University of Nottingham
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Oxford University Press (OUP)
Date: 20-08-2008
Abstract: In myometrium of pigs and rats, though not humans, relaxin appears to mediate an inhibition of spontaneous and oxytocin-induced contractility, presumably acting through a G-protein coupled receptor (RXFP1) to generate cAMP. In humans, circulating relaxin is highest in the first trimester, including the time of implantation, when transitory uterine quiescence could help a blastocyst to implant. We investigated whether relaxin can activate adenylate cyclase in primary human myometrial cells from non-pregnant tissue, and we show that relaxin is able to stimulate the generation of cAMP in a manner, which is dependent upon a tyrosine phosphorylation activity, as in the endometrium. We identified transcripts for the relaxin receptor RXFP1 as full-length variants, though a minor splice variant missing exon 2 was also present in low amounts. These cells also express transcripts encoding RXFP2, the receptor for the closely related hormone, INSL3. Although able to respond to relaxin at high concentrations, this receptor does not appear to function by contributing to the cAMP production in human myometrial cells, nor does INSL3 act as a functional agonist or antagonist of relaxin action. In conclusion, the inability of relaxin to inhibit contractility in human myometrial cells would appear to be due to events downstream of simple cAMP generation.
Publisher: Oxford University Press (OUP)
Date: 09-2009
DOI: 10.1095/BIOLREPROD.109.077552
Abstract: The Leydig cell-specific factor insulin-like peptide 3 (INSL3) is involved in testicular descent during embryo development, and has been suggested to regulate spermatogenesis and bone metabolism in the adult. Using a new, sensitive assay specific for rodent INSL3, we have mapped the secretion of INSL3 into peripheral blood in mice and during postnatal male rat development (in female rats, circulating INSL3 is at the level of detection). Maximum INSL3 is measured at Postnatal Day (PD) 40 in the rat and decreases to a significantly lower, stable value by PD60, indicating an "overshoot" effect in the establishment of Leydig cell functionality during the first wave of spermatogenesis. Aging rats ( approximately 24 mo) have markedly reduced circulating INSL3 levels, as do humans. Treatment of young adult rats with ethane dimethylsulfonate (EDS) leads to loss of mature Leydig cells and no detectable INSL3 in peripheral blood. INSL3 can be detected first at Day 27 after EDS treatment, returning to near normal levels by Day 37. Both primary rat Leydig cells and the mouse MA-10 tumor cell line secrete substantial amounts of INSL3 into the culture media in a constitutive manner, unregulated by common effectors, including hCG. Analysis of different testicular fluid compartments shows highest INSL3 concentration in the interstitial fluid (391.4 +/- 47.8 ng/ml). However, INSL3 evidently traverses the blood-testis barrier to enter the seminiferous compartment, rete testis, and epididymis in sufficient concentration to be able to address the specific INSL3 receptors (RXFP2) on post-meiotic germ cells and in the epididymis.
Publisher: Oxford University Press (OUP)
Date: 14-10-2011
Abstract: The human genome project has identified, besides ovarian relaxin (RLN), six other relaxin-like molecules (RLN3, H1-RLN, INSL3-6), most of which appear to be expressed in the testis and/or male reproductive system, together with four different G-protein-coupled receptors responsive to one or other of these peptides. Earlier work on relaxin in the male assumed the simplistic hypothesis of only a single relaxin-like entity. This review systematically examines the expression and physiology of relaxin-like molecules in the male reproductive system in order to reappraise the importance of this hormone system for male reproductive function. Although there are important species differences, only INSL3 and INSL6 appear to be generally expressed at a moderately high level within the testis, whereas ovarian RLN is consistently a major secretory product of the prostate epithelium. However, all members of this relaxin-like family appear to be expressed also at a low level in different organs of the male reproductive system, suggesting possible autocrine aracrine effects. The four receptors (RXFP1-4) for these peptides are also expressed to differing levels in both somatic and seminiferous compartments of the testis and in the prostate, supporting relevant functions for most members of this interesting peptide family. Recent studies of relaxin family peptides in prostate pathology highlight their functional importance in the clinical context as potential causative, diagnostic and therapeutic agents and warrant more specific and detailed studies of their roles also in regard to male fertility and other aspects of male reproductive function.
Publisher: Wiley
Date: 22-01-2008
DOI: 10.1111/J.1365-2605.2007.00857.X
Abstract: Environmental contaminants are known to act as thyroid disrupting chemicals (TDCs). Broadly defined, TDCs are xenobiotics that alter the structure or function of the thyroid gland, alter regulatory enzymes associated with thyroid hormone (TH) homeostasis or change circulating or tissue concentrations of THs. For THs, homeostasis is defined as the normal range of THs and TSH in circulation and tissues. TDCs include a wide range chemical structures that act through a variety of mechanisms. Concern about TDCs has increased because of the critical role that thyroid hormones play in brain development. A major uncertainty regarding the endocrine disrupting potential of environmental xenobiotics is the potential for additive, antagonistic or synergistic effects following exposure to mixtures. In addition, there are a number of uncertainties in both interpretation and extrapolation of results from studies of TDC mixtures. Extrapolation of data from laboratory animals to humans is tempered by uncertainty in how the mechanism(s)-of-action of the TDCs may differ between species. The variety of mechanisms by which TDCs alter thyroid homeostasis also yields a difficulty in determining at what level of biological organization to cumulate effects. Should it be at the molecular level, which could be chemical class specific or at the level of a downstream consequence (e.g. circulating hormone levels, brain biochemistry and behaviour) which would be mechanism-independent? To date, the limited data from TDC mixture studies suggest that dose addition is reasonably accurate in predicting the effects on serum T4 concentrations. Assessing the health risks of thyroid disruption by environmental xenobiotics will need to include an improved understanding of how ergent mechanisms alter THs and consequent adverse impacts on nervous system development.
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.FERTNSTERT.2012.12.023
Abstract: Neohormone systems are defined as evolutionarily new endocrine or paracrine adaptations that supplement basic physiologic functions and define mammalian success. The relaxin family of peptide hormones are typical neohormones. Because they define the specific mammalian aspects of reproductive physiology, such as viviparity with implantation and placentation, lactation, or in the male the necessary adaptations to sperm needed for successful internal fertilization, they offer excellent biomarkers for characterizing reproductive health and disease. For ex le, ovarian H2-relaxin aids implantation and the establishment of the placenta, and circulating levels are significantly altered in early miscarriage. In the fetus, testicular INSL3 is responsible for the first phase of testicular descent and may be disrupted in cryptorchidism. In the adult, INSL3 is believed to be involved as an antiapoptotic factor in germ cell survival (male) and follicle selection (female) and acts as an excellent measure of Leydig cell functional capacity, particularly in the aging male. INSL5 and INSL6 appear also to be involved in the maintenance of adequate spermatogenesis. With the development of robust immunoassays for various relaxin family members, we are progressively gathering baseline information about normal biomarker levels as well as their perturbations in a wide range of reproductive pathologies.
Publisher: Oxford University Press (OUP)
Date: 05-2008
Abstract: Rodent studies suggest that the peptide hormone insulin-like factor 3 (Insl3) made by the fetal testis is responsible for the first transabdominal phase of testicular descent, and may be affected by xenobiotics to disrupt male reproductive tract development. To date, there is very little information on the production of INSL3 by the human fetus during gestation. The objective of the present study was to determine the concentrations and time course during pregnancy of INSL3 and testosterone production in human fetuses and their associations with maternal characteristics, pregnancy complications and outcome. This is a retrospective cohort study in which women who contributed amniotic fluid specimens to a bank from 2003-2006 were followed to determine their pregnancy complications and pregnancy outcome. Amniotic fluid specimens were collected from the Reproductive Genetics Laboratory of the Hospital of the University of Pennsylvania subsequent to routine amniocentesis. INSL3 and total testosterone levels were measured in amniotic fluid (from n = 50 female, n = 237 male fetuses) by validated immunoassays and correlated with maternal characteristics, pregnancy complications and outcomes. INSL3 was only detectable in amniotic fluid from male fetuses, and highest levels occurred from weeks 15-17 of gestation. INSL3 concentration was positively associated with increased birth weight, the occurrence of pre-ecl sia and advanced maternal age, but not with testosterone levels. INSL3 concentration in human amniotic fluid is potentially predictive of fetal sex and pre-ecl sia, and presumably reflects the functioning of the fetal Leydig cell population.
Publisher: Frontiers Media SA
Date: 19-06-2017
Publisher: Springer New York
Date: 2007
DOI: 10.1007/978-0-387-74672-2_3
Abstract: The small peptide hormone relaxin is a member of a rapidly evolving family of hormones and growth factors, whose mode of action appears to be particularly adapted to purely mammalian physiology. It is representative of a new category of hormones, referred to as neohormones, which appear to have evolved specifically to accommodate the needs of viviparity, lactation and wound repair. The mechanism of receptor signalling has also evolved in this family, with older members using receptor tyrosine kinases and new members such as relaxin adopting 7-transmembrane G-protein coupled receptors. Although relaxin primarily generates cAMP as second messenger, studies of relaxin signalling show that this does not conform to a classic G-protein dependent activation of adenylate cyclase: it requires additional cytoplasmic components, it can involve further coupling to PI3-kinase and PKCzeta and it is absolutely dependent on a tyrosine kinase activity linked closely to the relaxin receptor. Relaxin may also independently activate glucocorticoid receptors. This ersity of signalling leads to a broad range of possible downstream transcriptional effects. Finally, in tissues where relaxin is known to be effective, there is often also local relaxin induction, lifying the effects of the endocrine hormone.
Publisher: Oxford University Press (OUP)
Date: 11-09-2018
Abstract: Insulin-like peptide 3 (INSL3) is a member of the relaxin family of neohormones which has evolved to address specifically mammalian aspects of reproduction related to viviparity and internal fertilization. It was originally identified as a major product of testicular Leydig cells and has proved to be an important biomarker of Leydig cell functional capacity. However, INSL3 is also produced by theca interna cells of growing antral follicles and is secreted into the bloodstream in phases corresponding to the number and health of the follicles. Moreover, gene silencing experiments have shown that INSL3 is essentially required for androstenedione synthesis, which is the major steroid precursor for the granulosa cells of antral follicles to produce oestrogens. Knockout studies in mice confirm that loss of INSL3 or its receptor in females leads to partial infertility, with reduced follicle numbers, ovulations and litter size. Circulating INSL3 concentration corresponds to the reproductive lifespan, beginning with puberty and declining at the menopause, and thus may contribute to the physiology of other organ systems, particularly those relevant for hormone replacement strategies. A literature review was carried out by exhaustive searching of literature databases (PubMed and Google Scholar) with the search terms INSL3, RLF, Ley-IL and RXFP2. We present the first comprehensive review of INSL3 and its specific receptor RXFP2, and their roles in the context of female reproductive physiology. Moreover, we highlight the potential involvement of INSL3 in female reproductive pathology, such as PCOS, its clinical application as a valuable biomarker of reproductive processes, and its potential for therapeutic interventions. In the female mammal, INSL3 is largely produced by the theca interna cells of growing antral follicles during the follicular phase of the menstrual (oestrous) cycle. Within the follicle, INSL3 acts via its G-protein-coupled receptor, RXFP2, in an autocrine aracrine manner to orchestrate and drive the production of the major steroid precursor androstenedione and its conversion by granulosa cells into oestrogens. These in turn create a positive feedback loop promoting the expression of more theca cell INSL3. This is countered by the follicular production of bone morphogenetic proteins and by the LH surge. Thus, the activity of the theca cell INSL3-RXFP2 system effectively determines the production of estradiol within an antral follicle through the follicular phase. INSL3 is also secreted into the circulation where it acts as a valuable biomarker to monitor the growth of antral follicles it is consequently increased in PCOS and decreased in women with premature ovarian failure (POF). As an endocrine factor, INSL3 may also influence bone metabolism and kidney function. Additionally, INSL3 or its analogues may prove valuable as an adjunct in hormone replacement therapy or to monitor or influence IVF protocols. The INSL3-RXFP2 system represents a new regulatory pathway essential for the proper functioning of growing antral follicles. We still know very little about its involvement in pathologies such as PCOS or POF, and its role as a new biomarker of female function needs to be explored more widely to improve diagnosis and treatment of ovarian dysfunction. We need to examine how INSL3 might be used to improve IVF protocols and outcomes. Opportunities should also be investigated in regard to the systemic application of INSL3 as a rejuvenant therapy, with positive effects on bone or kidney function, and possibly also for fertility regulation. Most research to date has involved animal models this now needs to be extended to include more human studies.
Publisher: Oxford University Press (OUP)
Date: 05-09-2013
Abstract: How does insulin-like factor 3 (INSL3) concentration in blood vary across the menstrual cycle in women? INSL3 is secreted by the theca interna cells of growing antral follicles and is phasic in its expression. The relaxin-like hormone INSL3 is known to be expressed in follicles of several mammal species, and was recently shown in cows to be specifically secreted into the bloodstream by growing antral follicles, corresponding to follicular waves. In males INSL3 is known to be acutely independent of the hormones of the hypothalamic-pituitary-gonadal axis, suggesting that in women INSL3 might be a novel biomarker for antral follicle recruitment and development. Two cohorts of women were studied. First, 18 healthy women of reproductive age were followed longitudinally for one and a half cycles, with blood s ling and hormone measurement every 2-3 days. A second cohort comprised a cross-sectional study of 909 women attending an infertility clinic, with a single blood s le taken at entry, together with other clinical and hormonal parameters. Blood s les from both retrospective cohorts were analyzed for INSL3 using a highly sensitive time-resolved fluorescent immunoassay, and data were analyzed in comparison with other clinical and hormonal parameters. For young healthy women of reproductive age, we showed a phasic expression of INSL3 corresponding to antral follicle growth in both the follicular and luteal phases of the cycle, which was significantly (P < 0.05) elevated compared with that during menses. For women attending an infertility clinic, those with diagnosed polycystic ovarian syndrome indicated significantly (P < 0.0005) greater circulating INSL3 levels and those with low ovarian reserve showed significantly (P < 0.002) decreased INSL3 values. These were retrospective studies and the results were obtained from natural cycles only, with their inherent variability. We show for the first time that INSL3 in women does vary across the menstrual cycle, and appears to reflect the number of growing antral follicles recruited within both follicular and luteal phases. The present retrospective study was largely supported by departmental funds. There were no competing interests.
Publisher: Frontiers Media SA
Date: 06-06-2017
Publisher: Medknow
Date: 14-01-2013
DOI: 10.1038/AJA.2012.138
Publisher: Wiley
Date: 03-03-2008
DOI: 10.1111/J.1365-2605.2008.00866.X
Abstract: The incidence of hypospadias is increasing in young boys, but it remains unclear whether human exposure to endocrine disrupting chemicals plays a role. Risk assessment is based on estimation of no-observed-adverse-effect levels for single compounds, although humans are exposed to combinations of several anti-androgenic chemicals. In a mixture (MIX) study with three androgen receptor antagonists, vinclozolin, flutamide and procymidone, rats were gavaged during gestation and lactation with several doses of a MIX of the three chemicals or the chemicals alone. External malformations of the male reproductive organs were assessed on PND 47 using a score from 0 to 3 (normal to marked) for hypospadias. Markedly increased frequencies were observed after exposure to a MIX of the three chemicals compared to administration of the three chemicals alone. Anogenital distance at PND 1, nipple retention at PND 13, and dysgenesis score at PND 16 were highly correlated with the occurrence of hypospadias, and MIX effects were seen at doses where each of the in idual chemicals caused no observable effects. Therefore, the results indicate that doses of anti-androgens, which appear to induce no hypospadias when judged on their own, may induce a very high frequency of hypospadias when they interact in concert with other anti-androgens.
Publisher: Proceedings of the National Academy of Sciences
Date: 25-03-2013
Abstract: Ovarian androgen synthesis is essential for normal ovarian follicle development and female fertility in animals and humans. However, ovarian androgen excess, a feature of the widespread polycystic ovarian syndrome in women, is detrimental to fertility and has other pathophysiological consequences. Our findings reveal the importance of the intraovarian growth factor insulin-like peptide 3 signaling for maintaining androgen production by ovarian theca cells and show that the suppressive action of bone morphogenetic proteins on androgen production is linked to their inhibitory effect on insulin-like peptide 3 signaling, likely mediated via down-regulation of the nuclear transcription factor steroidogenic factor-1.
Publisher: Public Library of Science (PLoS)
Date: 16-05-2011
Publisher: Oxford University Press (OUP)
Date: 28-03-2009
Abstract: BACKGROUND Insulin-like factor 3 (INSL3) is a neohormone that has evolved to address specific mammalian traits, in particular, the first phase of testicular descent towards the scrotum during mid-gestation. METHODS A thorough literature search was made in PubMed using the terms INSL3, as well as the older synonyms RLF and Ley-IL. RESULTS INSL3 is a major secretory product of the testicular Leydig cells in the fetus and in adult men, and in rodent models, reduction in fetal INSL3 expression is an early marker of the testicular dysgenesis syndrome. In women, it is produced in lower amounts by ovarian theca and luteal cells, and circulating levels are increased in women with polycystic ovarian syndrome. During pregnancy, there is evidence for an interaction regulating the feto-placental unit. The presence of INSL3 in amniocentesis s les taken at 12-14 weeks gestation is absolutely specific for male gender, and levels are predictive of subsequent pre-ecl sia and/or birthweight. INSL3 is also involved in adult traits, such as spermatogenesis and bone metabolism. In adult men, INSL3 is constitutively expressed and secreted into the bloodstream at a constant level, reflecting the number and/or functional capacity of the Leydig cells. In complete contrast, testosterone is highly variable within in iduals, is acutely responsive to fluctuations in the hypothalamic-pituitary-gonadal axis and appears to have marginal diagnostic value. INSL3 declines consistently with age in adult men. CONCLUSIONS INSL3 promises to become an important new diagnostic tool to characterize those men with late-onset hypogonadism and to add clinical diagnostic value at amniocentesis.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.MCE.2013.04.016
Abstract: Steroidogenic tissues such as the ovary, testes or adrenal glands are paradoxical in that they often indicate actions of steroid hormones within a dynamic range of ligand concentration in a high nanomolar or even micromolar level, i.e. at the natural concentrations existing within those organs. Yet ligand-activated nuclear steroid receptors act classically by direct interaction with DNA in the picomolar or low nanomolar range. Moreover, global genomic studies suggest that less than 40% of steroid-regulated genes involve classical responsive elements in gene promoter regions. The bovine oxytocin gene is a key element in the maternal recognition of pregnancy in ruminants and is regulated via an SF1 site in its proximal promoter. This gene is also regulated by steroids acting in a non-classical manner, involving nuclear receptors which do not interact directly with DNA. Dose-response relationships for these actions are in the high nanomolar range. Similar 'steroid sensing' mechanisms may prevail for other SF1-regulated genes and predict alternative pathways by which environmental endocrine disruptors might influence the functioning of steroid-producing organs and hence indirectly the steroid-dependent control of physiology and development.
Publisher: Oxford University Press (OUP)
Date: 17-04-2013
DOI: 10.1095/BIOLREPROD.113.108969
Abstract: Insulin-like factor 3 (INSL3) is a small peptide hormone made and secreted uniquely by mature Leydig cells in the testes of all mammals. Importantly, this expression and secretion appears to be constitutive and therefore reflects the differentiation status and number of the Leydig cells present, differing thereby from testosterone, which is acutely and homeostatically regulated by the hormones of the hypothalamic-pituitary-gonadal axis. As a consequence, the measurement of INSL3 either as mRNA in the testis or as secreted peptide circulating in the blood provides an excellent assessment of Leydig cell differentiation, for ex le, during fetal development, puberty, or aging or following exposure to endocrine-disrupting agents. Whereas INSL3 is proving increasingly useful as a biomarker for testis status, less is known about its functions, particularly in the adult male. Current evidence points to autocrine, paracrine, and endocrine roles, acting through the G-protein-coupled receptor called RXFP2, although more research is required to characterize these functions in detail.
Publisher: Wiley
Date: 05-2005
Abstract: The heterodimeric peptide hormone relaxin in most cells appears to signal through a G-protein-coupled receptor, LGR7. Whereas in artificial cell systems, made by transfection of receptor-expressing gene constructs into cells normally not presenting the receptor, classic activation of adenylate cyclase appears to be mediated by Gs, in cells naturally expressing the receptor, this type of coupling appears to be very weak. Instead, there is good evidence of other intermediate steps involving cytoplasmic components and tyrosine kinase activity. Part of the complexity of relaxin signaling is also manifest in the variable time course of cAMP production evident in the THP-1 cell line, which appears to depend on passage number and, hence, presumably on differentiation status. It is therefore important to distinguish between immediate early effects, short to mid-term responses, and long-term responses likely the consequences of specific gene upregulation.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2015
Publisher: Wiley
Date: 03-10-2006
DOI: 10.1111/J.1365-2605.2006.00714.X
Abstract: The novel peptide hormone insulin-like peptide 3 (INSL3) is a major secretory product of the Leydig cells of the testis, and in adult men is secreted into the blood, giving rise to circulating concentrations ranging from 0.5 to 2.5 ng/mL. We studied a large randomly recruited cohort of 1183 men from South Australia, comparing serum INSL3 concentrations with age, and a variety of endocrine, cognitive and morphological parameters. While INSL3 concentration declines significantly (p < 0.001) and continuously with age from 1.29 +/- 0.47 ng/mL in young men (age 35-44 years) to 0.79 +/- 0.39 ng/mL in the age group 75-80 years, there is no correlation with testosterone or components of the hypothalamo-pituitary-gonadal (HPG) axis, independent of age, nor with any other parameter measured, including thyroid or prostate status and obesity. For men exhibiting normal follicle stimulating hormone (FSH) and high luteinizing hormone (LH) levels, there was a significant inverse correlation with plasma oestradiol. Unilaterally orchidectomized men had INSL3 values intermediate between intact men and anorchid subjects, and showed inverse correlations (p < 0.001) between INSL3 and FSH or LH concentrations, which were independent of age. Taken together, the data show that INSL3 is an independent measure of Leydig cell function (quality and number), which appears to be independent of acute control via the HPG axis. Its decline with age reflects a decline in the properties of the Leydig cell population only, and emphasizes a gonadal component in the age-related decrease in androgen production.
Publisher: Wiley
Date: 27-02-2017
DOI: 10.1111/BPH.13689
Publisher: Frontiers Media SA
Date: 2014
Publisher: Bioscientifica
Date: 04-2014
DOI: 10.1530/REP-13-0435
Abstract: Insulin-like factor 3 (INSL3) is a promising marker of Leydig cell function with potentially high clinical relevance. Limited data of INSL3 levels in relation to other reproductive hormones in healthy pubertal boys exist. In this study, we aimed to evaluate longitudinal serum changes in INSL3 compared with LH, FSH, testosterone, inhibin B, and anti-Müllerian hormone (AMH) during puberty in healthy boys. Ten boys were included from the longitudinal part of the COPENHAGEN Puberty Study. Pubertal evaluation, including testicular volume, was performed and blood s les were drawn every 6 months for 5 years. Serum concentrations of testosterone were determined by a newly developed LC–MS/MS method, and serum concentrations of INSL3, AMH, inhibin B, FSH, and LH respectively were determined by validated immunoassays. The results showed that serum INSL3 levels increased progressively with increasing age, pubertal onset, and testicular volume. In six of the ten boys, LH increased before the first observed increase in INSL3. In the remaining four boys, the increase in LH and INSL3 was observed at the same examination. The increases in serum concentrations of LH, testosterone, and INSL3 were not parallel or in ordered succession and varied interin idually. We demonstrated that INSL3 concentrations were tightly associated with pubertal onset and increasing testicular volume. However, the pubertal increases in LH, INSL3, and testosterone concentrations were not entirely parallel, suggesting that INSL3 and testosterone may be regulated differently. Thus, we speculate that INSL3 provides additional information on Leydig cell differentiation and function during puberty compared with traditional markers of testicular function.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.MCE.2013.08.010
Abstract: The relaxin family of peptide hormones are structurally closely related to one another sharing a heterodimeric A-B structure, like that of insulin. They may also be active as unprocessed B-C-A pro-forms. Relaxin has been shown to pay a key role within the ovary, being involved in follicle growth, and ovulation. Relaxin is produced in large amounts also by the corpus luteum where it acts as an endocrine hormone positively affecting implantation, placentation and vascularization during the all-important first trimester phase of pregnancy establishment. Relaxin exerts its functions via the receptor RXFP1. Insulin-like peptide 3 (INSL3) in contrast acts through the related receptor RXFP2, and plays an essential role in the production of androgens within growing antral follicles. INSL3 is also produced in large amounts by the male fetus shortly after sex determination, where it controls the first transabdominal phase of testicular descent. However, this fetal INSL3 is also able to influence placental and maternal physiology, indicating associations with later preecl sia and/or fetal growth restriction. Other members of this relaxin-like family of peptides, such as INSL4, INSL5 and INSL6 are less well studied, though all suggest modulatory roles in ovarian and/or placental function.
Publisher: Elsevier BV
Date: 09-2005
DOI: 10.1016/J.MCE.2005.03.017
Abstract: Insulin-like factor 3 (Insl3) is a major new product of the Leydig cells in all mammalian species so far examined. The rat Insl3 gene is encoded by two exons in close juxtaposition to the Jak3 gene. Using RT-PCR analysis we now show that in the rat testis it is expressed as both major and minor splice variants, the former encoding the normal protein, the latter a truncated peptide comprising a C-terminally extended B-domain. Both transcripts are produced in constant relative amounts uniquely in the Leydig cells of the postnatal testis and in no other testicular cell type. Rat Insl3 protein is also expressed only in Leydig cells after postnatal day 30. Although specific mRNA is present at earlier times, corresponding protein is not detected. Semi-quantitative RT-PCR analysis of Insl3 transcripts in the mouse MA-10 tumour Leydig cell-line under a wide range of stimulation regimes shows that in an acute context, the Insl3 gene is expressed absolutely constitutively. This is confirmed by transfection and electrophoretic mobility shift (EMSA) analysis of the rat Insl3 gene promoter, wherein the importance of three putative SF-1 responsive elements is underscored, although these appear to differ in their relative importance from their counterparts in the mouse Insl3 gene.
Publisher: Wiley
Date: 24-03-2021
DOI: 10.1111/ANDR.13001
Abstract: Insulin‐like peptide 3 (INSL3) is a constitutive, secreted peptide produced in the male uniquely by the Leydig cells of the testes. It is a biomarker for Leydig cell functional capacity, which is a measure of the numbers and differentiation status of these steroidogenic cells and lacks the biological and technical variance of the steroid testosterone. This retrospective study was carried out to examine the relationship between seminal parameters and the Leydig cell compartment, and secondarily to assess other factors responsible for determining Leydig cell functional capacity. INSL3 was assessed together with seminal, anthropometric, and hormonal parameters in a Swedish cohort of 18‐year‐old men, representing the average population, and in a smaller, more heterogeneous cohort of men visiting an Australian infertility clinic. Average INSL3 concentration at 18 years is greater than that reported at younger or older ages and indicated a large 10‐fold variation. In neither cohort was there a relationship between INSL3 concentration and any semen parameter. For the larger, more uniform Swedish cohort of young men, there was a significant negative relationship between INSL3 and BMI, supporting the idea that adult Leydig cell functional capacity may be established during puberty. In both cohorts, there was a significant relationship between INSL3 and FSH, but not LH concentration. No relationship was found between INSL3 and androgen receptor trinucleotide repeat polymorphisms, reinforcing the notion that Leydig cell functional capacity is unlikely to be determined by androgen influence alone. Nor did INSL3 correlate with the T/LH ratio, an alternative measure of Leydig cell functional capacity, supporting the view that these are independent measures of Leydig cell function.
Publisher: Environmental Health Perspectives
Date: 2016
DOI: 10.1289/EHP.1409288
Publisher: Wiley
Date: 13-12-2012
DOI: 10.1111/J.1365-2605.2011.01231.X
Abstract: The manner by which endocrine-disrupting xenobiotics, such as phthalates, can induce changes in the development of the male reproductive system still remains largely unknown. Herein, we have explored the application of ethane dimethane sulphonate (EDS) to eliminate adult-type Leydig cells in the mature rat testis, leading to their regeneration from resident stem cells, as a novel system to investigate the effects of dibutyl phthalate (DBP) and diethylstilbestrol (DES) on adult-type Leydig cell differentiation. The advantage of this model is that one can study adult-type Leydig cell differentiation in vivo orced from the concomitant endocrine development of puberty. In these preliminary studies, we show that both DBP and/or DES, given for 2 or 4 days following EDS application, indeed affect Leydig cell differentiation in the adult testis, largely by increasing early Leydig cell proliferation and possibly thereby delaying early differentiation. In particular, on day 27 post-EDS, a time-point when the differentiation trajectory appears to be most discriminating, we observe that both DBP and/or DES cause a fourfold increase in Leydig cell density, and a significant increase in the expression of the Leydig cell-specific marker transcripts INSL3, LH receptor, Cyp17a1 and Cyp 11a1. In conclusion, both DBP and DES are able to affect adult-type Leydig cells during their differentiation to cause a significant perturbation in their ultimate functional capacity.
Publisher: Public Library of Science (PLoS)
Date: 15-06-2016
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2011
Publisher: Oxford University Press (OUP)
Date: 05-2006
DOI: 10.1095/BIOLREPROD.105.048165
Abstract: The new peptide hormone insulin-like peptide 3 (INSL3) is a member of the insulin-relaxin family, yet, unlike insulin, it signals through a new G-protein coupled receptor, LGR8, distantly related to the receptors for LH and FSH. INSL3 is produced in large amounts by the Leydig cells of the testis in both fetal and adult mammals. Using a combination of mRNA analysis by RT-PCR, immunohistochemistry, ligand-binding, and/or bioactivity assays, the distribution of LGR8 expression was assessed in testicular tissues and cells and in the epididymis. There was consistent agreement that LGR8 was expressed in meiotic and particularly postmeiotic germ cells and in Leydig cells, though not in Sertoli or peritubular cells. Leydig cells appear to express only a low level of the LGR8 gene product other transcripts may be present, representing nonfunctional products. Messenger RNA analysis suggested that LGR8 transcripts in germ cells represented mostly full-length forms. LGR8 mRNA was also expressed in the epididymis, though no function can yet be ascribed to this expression. Therefore, the INSL3/LGR8 system represents a further paracrine hormone-receptor system in the testis, which conveys information about Leydig cell status to germ cells, and possibly as part of an autocrine feedback loop.
Publisher: Public Library of Science (PLoS)
Date: 31-03-2016
Publisher: Public Library of Science (PLoS)
Date: 21-11-2019
Publisher: The Endocrine Society
Date: 07-2003
DOI: 10.1210/EN.2002-0082
Abstract: Expression of the new 17β-hydroxysteroid dehydrogenase (HSD), type 10 (17β-HSD-10), formerly known as endoplasmic reticulum-associated amyloid-binding protein, has been investigated in the testes of various mammals under normal and perturbed conditions. Results show that 17β-HSD-10 is a major product of both fetal and adult-type Leydig cells. In the former, protein persists until late in postnatal development and in the short-day hamster model, it does not disappear when Leydig cells involute. During puberty in the rat, immunohistochemical staining for 17β-HSD-10 in adult-type Leydig cells first becomes evident on d 20, increasing to maximal staining intensity by d 35. In the rat, but not in the mouse or any other species examined, there is also staining in late spermatids. Examination of testes from rats subjected to perinatal treatment with either a GnRH antagonist or low and high doses of diethylstilbestrol revealed that expression of 17β-HSD-10 follows closely Leydig cell differentiation status, correlating with 3β-HSD expression in a previous study. In aging (23 months) rat testes, Leydig cell (but not germ cell) immunostaining for 17β-HSD-10 is markedly reduced. 17β-HSD-10 seems to preferentially convert 3α-androstanediol into dihydrotestosterone, and estradiol to estrone. Thus, perinatal expression of this enzyme in fetal Leydig cells may contribute to protecting these cells from estrogens and encourage androgen formation.
Publisher: Portland Press Ltd.
Date: 27-05-2011
DOI: 10.1042/BJ20110766
Abstract: Spermatozoa represent a highly specialized cell type, with a minimalist structure designed to fulfil a single principal function: the transport of an intact single-copy haploid genome to the site of fertilization in the oviduct, and consequent zygote formation. They have lost most of their original cytoplasm, and remaining organelles are extremely modified. One result of this is that biochemical dynamics are restricted by a lack of cytoplasmic diffusion and a dramatic compartmentalization, with an increased emphasis on the physicochemical modulation of membranes. This is also reflected in a truncated apoptotic pathway, described in this issue of the Biochemical Journal in an article by Koppers et al., which leads to a so-called ‘silent response’ in the female tract, whereby unused sperm are removed without inflammatory consequences that might otherwise be detrimental to the new embryo. This new study shows that sperm have not simply jettisoned unwanted cellular components, but have evolved a very appropriate systems biology adapted to the specialist role they have to perform.
Publisher: Elsevier BV
Date: 06-2007
DOI: 10.1016/J.MCE.2007.04.001
Abstract: The heterodimeric peptide hormone relaxin acts through the novel G-protein coupled receptor LGR7 to elicit the production of cAMP in the human monocyte cell line THP-1. The very small number of receptors on the cell surface, and the lack of response in cell membranes imply the involvement of a cytoplasmic signal lification process. Here we show that this process comprises a novel and specific tyrosine kinase activity close to the receptor, and involves neither protein kinase A, mitogen-activated protein kinase, nor phosphoinositide-3 kinase activities as major upstream components. Furthermore, this novel involvement of a tyrosine kinase activity is cell-type dependent, being largely absent from LGR7-transfected HEK293T cells, and receptor-dependent vasoactive intestinal peptide or isoproterenol signalling in the same cells does not require this tyrosine kinase activity.
Publisher: Elsevier BV
Date: 03-2015
DOI: 10.1016/J.FERTNSTERT.2014.11.014
Abstract: To elucidate the natural course of circulating insulin-like peptide 3 (INSL3) levels according to puberty as well as its relation to other reproductive hormones. Population-based cohort study. Not applicable. Healthy peripubertal girls (n = 10) examined every 6 months total number of examinations was 84 median (range) per girl: 9 (4-10), including staging of pubertal breast development and blood s les. None. Serum levels of INSL3, inhibin B, E2, antimüllerian hormone, LH, and FSH (validated immunoassays), and T and androstenedione (liquid chromatography-tandem mass spectrometry). Serum levels of INSL3 varied considerably between girls (range, 0.01-0.27 ng/mL) and within each girl as puberty progressed intrain idual variation, median (range) 102% (65%-143%). Insulin-like peptide 3 increased in late puberty (B1 to B4+B5) geometric mean 0.03 ng/mL to 0.15 ng/mL. Insulin-like peptide 3 levels reflected markers of large follicles (T, androstendione, inhibin B, and E2) better than markers of small follicles (antimüllerian hormone), and INSL3 staining was localized in theca interna cells of antral follicles. Insulin-like peptide 3 increased in late puberty, albeit inter- and intrain idual variations were substantial. Immunohistochemistry and intrain idual variation, as well as relations to other ovarian hormones, reveal that INSL3 in girls is a unique and specific marker of theca cells surrounding antral follicles. The potential clinical use of INSL3 for evaluation of ovarian function in girls remains to be elucidated.
Publisher: Oxford University Press (OUP)
Date: 08-2014
Publisher: The Endocrine Society
Date: 04-2013
DOI: 10.1210/EN.2012-2232
Abstract: Insulin-like peptide 3 (INSL3), a major product of testicular Leydig cells, is also expressed by the ovary, but its functional role remains poorly understood. Here, we quantified expression of INSL3 and its receptor RXFP2 in theca interna cell (TIC) and granulosa cell compartments of developing bovine antral follicles and in corpora lutea (CL). INSL3 and RXFP2 mRNA levels were much higher in TIC than granulosa cell and increased progressively during follicle maturation with INSL3 peaking in large (11-18 mm) estrogen-active follicles and RXFP2 peaking in 9- to 10-mm follicles before declining in larger (11-18 mm) follicles. Expression of both INSL3 and RXFP2 in CL was much lower than in TIC. In situ hybridization and immunohistochemistry confirmed abundant expression of INSL3 mRNA and protein in TIC. These observations indicate follicular TIC rather than CL as the primary site of both INSL3 production and action, implying a predominantly autocrine aracrine role in TIC. To corroborate the above findings, we showed that in vitro exposure of TIC to a luteinizing concentration of LH greatly attenuated expression of both INSL3 and its receptor while increasing progesterone secretion and expression of STAR and CYP11A1. Moreover, in vivo, a significant cyclic variation in plasma INSL3 was observed during synchronized estrous cycles. INSL3 and estradiol-17β followed a similar pattern, both increasing after luteolysis, before falling sharply after the LH surge. Thus, theca-derived INSL3, likely from the dominant preovulatory follicle, is detectable in peripheral blood of cattle, and expression is down-regulated during luteinization induced by the preovulatory LH surge. Collectively, these findings underscore the likely role of INSL3 as an important intrafollicular modulator of TIC function/steroidogenesis, while raising doubts about its potential contribution to CL function.
Publisher: Wiley
Date: 05-2005
Abstract: Insulin-like factor 3 (INSL3), previously known as the relaxin-like factor (RLF), is a major peptide hormone secreted from the testicular Leydig cells of adult men and circulating in the blood at a concentration of approximately 1 ng/mL. Women also produce INSL3 in the theca interna cells of ovarian follicles, but circulating levels remain below 100 pg/mL. INSL3 is structurally related to relaxin and insulin, but unlike the latter, signals through a novel G-protein-coupled receptor, LGR8. Ablation of the gene for INSL3 leads primarily to cryptorchidism because of a defect in the first, transabdominal phase of testicular descent. In the adult knockout mouse, a mild phenotype is evident in the testis and ovary. We have developed a panel of antibodies specific for INSL3 from various species, which are suitable for immunohistochemistry and, more recently, for immunoassays. INSL3 is an important marker for the mature Leydig cell phenotype, where it appears to be expressed constitutively, once the mature differentiation state is achieved. It is also an indicator of differentiation status not only for Leydig cells but also for the theca interna cells of the ovary.
Publisher: Bioscientifica
Date: 04-2014
DOI: 10.1530/REP-13-0486
Abstract: Insulin-like factor 3 (INSL3) is generated and secreted by differentiated interstitial Leydig cells of the testes in both fetal and adult males of all mammalian species so far analyzed. All evidence to date suggests that it is produced constitutively, independently of acute regulation by the hypothalamo-pituitary–gonadal (HPG) axis, in amounts which reflect the numbers and differentiation status of the Leydig cells. This Leydig cell functional capacity is otherwise monitored only by androgen output, which, however, is massively confounded by acute regulation from the HPG axis and other factors leading to substantial and irregular short-term variation. Leydig cells are a primary target of endocrine-disrupting agents in the context of the testicular dysgenesis syndrome in the fetal male, as well as in the adult. In the male fetus, INSL3 is responsible for the first phase of testicular descent, and hence is directly linked to the etiology of cryptorchidism. In this study, by measuring INSL3 production, for ex le, during fetal life via amniotic fluid, or as secretions from fetal testis explants, or in adult peripheral blood, we and others have shown that INSL3 represents a useful quantitative and sensitive endpoint for assessing the impact of endocrine-disrupting agents and their mechanisms of action.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Ravinder Anand-Ivell.