Effects Of Leptin On Follicle Growth And Ovulation
Funder
National Health and Medical Research Council
Funding Amount
$196,470.00
Summary
Leptin is a recently discovered hormone which is very important in controlling body weight. Extremely obese, or extremely underweight women, find it difficult to become pregnant, and leptin is probably the connection between weight and fertility. This may be a particularly important factor in polycystic ovary syndrome (PCOS), a distressing condition which affects 5% of women and causes both obesity and infertility. Exciting new research suggests that leptin also affects the immune system, and pr ....Leptin is a recently discovered hormone which is very important in controlling body weight. Extremely obese, or extremely underweight women, find it difficult to become pregnant, and leptin is probably the connection between weight and fertility. This may be a particularly important factor in polycystic ovary syndrome (PCOS), a distressing condition which affects 5% of women and causes both obesity and infertility. Exciting new research suggests that leptin also affects the immune system, and previous NH and MRC funding has enabled us to demonstrate that the immune system plays a crucial role in maintaining normal ovarian function. The nutritional status of the body, the immune system and the reproductive system all interact, and leptin appears to be the connecting link between these three major systems. We propose that leptin plays a major role in the ovary, and wish to determine how leptin mediates the effects of bodyweight and the immune system on ovarian function. Laboratory rats will be treated with leptin, their food intake and weight recorded, and a few weeks later the rats will have their ovaries removed. We will find out whether ovaries respond to leptin, or whether the ovarian response changes according to the menstrual cycle: perhaps leptin is very important just before ovulation, but it does not affect menstruation? Do any ovarian cells make leptin? Will leptin stimulate ovaries to produce more oestrogen or progesterone, or ovulate more eggs? We will also identify immune system cells in the ovary, and note whether leptin affects them. We will be able to relate all this data to weight and diet. Increased understanding of leptins' effect on the ovary has the potential to lead to new, improved treatments for PCOS or for unexplained cases of infertility. It is also possible that in the future a weight-loss regime might be developed which takes a womans monthly cycle into account, therefore making weight-loss more efficient and attainable.Read moreRead less
Neuroendocrine Mechanisms By Which Leptin Regulates Reproduction
Funder
National Health and Medical Research Council
Funding Amount
$447,750.00
Summary
The reproductive system is sensitive to alterations in body weight. In particular, low body weight causes the reproductive system to cease functioning. This is because the brain 'senses' metabolic status and responds by ceasing to secrete the brain hormone that drives the reproductive process. This hormone is gonadotropin releasing hormone that acts on the pituitary gland to control the release of gonadotropins. These, in turn, act on the gonads. How the brain perceives metabolic status is not k ....The reproductive system is sensitive to alterations in body weight. In particular, low body weight causes the reproductive system to cease functioning. This is because the brain 'senses' metabolic status and responds by ceasing to secrete the brain hormone that drives the reproductive process. This hormone is gonadotropin releasing hormone that acts on the pituitary gland to control the release of gonadotropins. These, in turn, act on the gonads. How the brain perceives metabolic status is not known. Leptin is a hormone that is produced by fat and acts on the brain. This appears to be one of the means by which the reproductive system is regulated. Leptin also regulates food intake and other brain processes. Leptin acts on specific cell types in the brain. Some of these may have dual function to regulated appetite as well as reproduction. The present proposal is for work to determine mechanisms within the brain that are altered by leptin. We will also determine which specific mechanisms relate to the regulation of gonadotropin releasing hormone. The work will provide information on how putative appetite regulators might affect the reproductive axis. Such work will provide a platform for design of pharmaceutical means to manipulate the reproductive axis and will impact on the design of drugs that regulate obesity. It is possible that drugs that developed to control obesity may affect the reproductive axis and the project will identify these.Read moreRead less