Sex Differences In The Mechanisms By Which Stress Inhibits The Secretion And Actions Of GnRH
Funder
National Health and Medical Research Council
Funding Amount
$408,055.00
Summary
It is well known that stress can impair reproduction in humans and animals but it is not understood how this occurs. Consequently there are no therapies available to overcome the detrimental effects of stress on reproduction. Stress can take many forms, such as psychological stress, surgical trauma, strenuous exercise, undernutrition, all of which may inhibit reproduction. We now know that males and females respond differently to stress and we have shown that stress is also likely to have differ ....It is well known that stress can impair reproduction in humans and animals but it is not understood how this occurs. Consequently there are no therapies available to overcome the detrimental effects of stress on reproduction. Stress can take many forms, such as psychological stress, surgical trauma, strenuous exercise, undernutrition, all of which may inhibit reproduction. We now know that males and females respond differently to stress and we have shown that stress is also likely to have different effects on reproduction in males and females. In this project we aim to determine how stress impairs reproduction in males and females. A major effect of stress appears to be to inhibit the secretion of a substance produced by the brain that is necessary for the regulation of reproduction. This substance is called gonadotrophin releasing hormone (GnRH) and it acts on a small gland at the base of the brain to cause the release of hormones that are essential for reproduction in both males and females. It is also possible that stress may inhibit the actions of GnRH. Our research suggests that there may be differences between males and females in the extent to which stress inhibits the secretion of GnRH from the brain and its actions to cause the release of other reproductive hormones. In this project we will determine how stress acts in the brain to affect the secretion and actions of GnRH in males and females. Our research will make a major contribution to our knowledge of the way that stress inhibits reproduction in males and females. This information is essential in order to develop specific remedies to overcome reproductive disorders caused by stress and to improve reproductive health in both sexes.Read moreRead less
Investigating The Physiological And Clinical Differences In Weight Loss In Obese Subjects With And Without Diabetes.
Funder
National Health and Medical Research Council
Funding Amount
$101,726.00
Summary
Obesity and type 2 diabetes are linked by the production of inflammatory factors in the body. These factors seem to link weight gain, especially around the abdomen, not only with insulin resistance, the precursor to diabetes, but also independently with the development with heart and kidney disease and reduced fertility. This study will investigate the effect of dieting and weight loss on inflammation and the function of the heart and other organs in obese people with and without diabetes.
Interactions Between Advanced Glycation And Oxidative Stress In Diabetic Renal And Cardiac Complications
Funder
National Health and Medical Research Council
Funding Amount
$431,700.00
Summary
Kidney and heart disease are serious complications of diabetes. These complications are the major cause of disability and premature death in the western world. Studies from our group and others have shown that diabetic complications appear to be a consequence of a number of different processes. These pathways include a sugar dependent pathway of irreversible interactions between proteins such as collagen and sugar known as advanced glycation. The process of advanced glycation alters the body's a ....Kidney and heart disease are serious complications of diabetes. These complications are the major cause of disability and premature death in the western world. Studies from our group and others have shown that diabetic complications appear to be a consequence of a number of different processes. These pathways include a sugar dependent pathway of irreversible interactions between proteins such as collagen and sugar known as advanced glycation. The process of advanced glycation alters the body's ability to renew these protein, hence causing accelration of the ageing process. In fact, it is estimated that this process occurs almost fifty times faster in diabetes. These sticky complexes accumulate in tissues causing disruption ot the normal tissue structure. Our group has a drug which can act as scissors and cut the sticky sugar off the proteins allowing it to be turned over. Unfortunately this does not fix all of the damage. These AGE molecules are involved in a number of other harmful processes including the production of toxic oxygen derived molecules which are harmful byproducts of diabetes. While these oxygen 'radicals' have been implicated in heart attack and stroke their source has remained a mystery in diabetes. Previously, the only way to remove these molecules was to mop them up with antioxidants such as Vitamin E. Antioxidants work slowly and so some damage is already done before they 'detoxify' these oxygen radicals. We propose to use combinations of medicines to see if we can achieve more effective protection against these processes in experimental diabetes. This may provide new therapies for threatment of kidney and heart disease in diabetes.Read moreRead less
Mineralocorticoid Receptor Co-regulator Recruitment Determines Ligand Specific Signalling.
Funder
National Health and Medical Research Council
Funding Amount
$491,530.00
Summary
Heart disease is a major cause of death and economic burden in Australia and throughout the world. The steroid hormone aldosterone controls salt and water balance,blood pressure and hasa significant role in heart failure. Although drugs that block the aldosterone receptor significantly help patients with heart failure, their use is limited by side effects. This work will identify the profile of proteins that promote aldosterone effects and enable the development of heart-specific blockers.
Regulation And Effect Of The Growth Hormone, IGF-I, And IGF-Binding Protein Response To Acute Exercise
Funder
National Health and Medical Research Council
Funding Amount
$367,197.00
Summary
The body's ability to respond to physiological stress is vital to survival. This series of studies aims to examine the hormonal responses to physical exercise. In studies recently completed to determine how to detect Growth Hormone (GH) abuse in the Olympics, we have discovered a new system of hormones that respond to exercise. These Insulin-like Growth Factors (IGF) and their IGF-Binding Proteins (IGF-BP) are normally controlled by GH. The IGF-IGF-BP system normally acts to control of many cell ....The body's ability to respond to physiological stress is vital to survival. This series of studies aims to examine the hormonal responses to physical exercise. In studies recently completed to determine how to detect Growth Hormone (GH) abuse in the Olympics, we have discovered a new system of hormones that respond to exercise. These Insulin-like Growth Factors (IGF) and their IGF-Binding Proteins (IGF-BP) are normally controlled by GH. The IGF-IGF-BP system normally acts to control of many cellular and organ functions in many different tissues of the body. For example they stimulate protein accumulation and muscle growth, and have actions to control blood glucose in conditions like diabetes. Little is known about what regulates the production of the IGF and IGF-BPs in response to physical exercise. We aim to examine whether GH, either as an acute pulse as occurs naturally, or a direct effect of exercise that is not GH-mediated, is responsible for the increase in IGF and IGFBPs. This may uncover a new means of controlling this powerful hormonal system. In addition, we will examine whether GH or IGF-I, alone and together, influence the body's ability to respond to the stress of exercise (e.g., controlling fuel use, cardiovascular and kidney responses). Such information will allow greater understanding of this important hormonal system, so that in novel therapies may be developed for conditions such as normal ageing, the wasting states that accompany severe surgical or infectious stress, or conditions with abnormal blood glucose regulation such as diabetes. In addition, this information will permit greater sophistication in the detection of GH and related compounds in elite athletes. Unfortunately, GH is also being abused by non-elite athletes and high-school children. We believe our efforts will asist in the detection and prevention of these more general societal health issues.Read moreRead less