Endocrine Abstracts

The brain controls reproduction through the secretion of GnRH, but a series of higher brain centres control the secretion of GnRH into the hypophysial portal system. Whereas GnRH might be considered the ‘speaker’ for the brain in the reproductive axis, there is significant ‘cross-talk and chatter’ relating to the higher brain centres of control. Most prominently, kisspeptin mediates the feedback effect of sex steroids on GnRH cells, which may be effected at...

Professor Clarke graduated from Massey University, New Zealand (B. Agric. Sci., 1971) followed by M. Agric. Sci. (1st Class) in reproductive physiology in 1973). He then obtained his PhD at Edinburgh University, Scotland in 1976, studying endocrinology and behaviour. He has since moved to Australia and became Senior Research Fellow of NHMRC in 1986, rising to Principal Research Fellow in 1991. He became Chairman, D...

As a general rule, hypothalamic neuropeptides that stimulate food intake act to inhibit the reproductive axis. We have studied the functions of two peptide systems in detail. Melanocortins, such as melanocyte stimulating hormone-α, β and γ, are products of the pro-opiomelanocortin (POMC) gene, produced in cells of the arcuate nucleus and act to inhibit feeding. Melanocortins also stimulate the reproductive axis. In lean hypogonadotropic ovariectomised ewes, POMC...

Evidence from studies in goats1, sheep2 and mice3 suggests that the kisspeptin cells of the arcuate nucleus generate the signal that causes the pulsatile secretion of GnRH. This effect may be due to action of kisspeptin on GnRH terminals in the median eminence3,4. We conducted studies on sheep to test the hypothesis that kisspeptin cells of the arcuate nucleus (ARC) and/or the glutamate cells of the hypothalamus pulses of GnRH secret...

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy of reproductive age women and is characterized by reproductive, metabolic and psychological features exacerbated by weight gain. Weight management in PCOS is challenged by propensity to weight gain and lack of sustainable dietary interventions. Body weight is regulated by calorie intake and the rate of energy expenditure. Metabolically active brown adipose tissue (BAT), contributing to energy dissipation, has b...