Effect of leptin on LH and FSH release in ovariectomized rats

We compared the estradiol/progesterone-induced luteinizing hormone [LH] and follicle-stimulating hormone [FSH] release between normally fed and leptin-supplemented starved ovariectomized female rats and studied also the effect of hyper-leptinaemia on the steroid-induced hormonal release in normally fed ovariectomized rats. Three days' starvation completely abolished steroid-induced LH and FSH release. Significant recovery of the hormonal release was shown in the leptin-supplemented starved group. The magnitudes of LH and FSH release in the normally fed animals with a higher dose of leptin were statistically the same as those in the normally fed group without leptin. These observations indicate that physiological concentrations of circulating leptin exert a stimulatory effect on steroid-induced LH and FSH release

Effect of acute central administration of neuropeptide y [NPY] on gonadotropic ovarian axis in adult female rats

Eighteen female albino rats were used in this study. They were subdivided into 3 groups each of 6 animals, first group is formed of normal control, injected intra cerebroventricularly [ICV] with normal saline. Second group [low dose NPY group] where animals were injected with 30 microg/kg NPY by the ICV route, the 3rd group [high NPY group] the animals were injected by 70/microg/kg NPY by the same route. Two hours later after injection, serum level of lutienizing hormone [LH], follicle stimulating hormone [FSH], oestrogen and progesterone were estimated for all the 3 groups. The study revealed a significant increase in FSH, significant decrease of LH and non significant change in oestrogen and progesterone levels in animals injected with low dose of NPY. High NPY injected animals showed significant increase in FSH and oestrogen, significant decrease in LH, non significant change in progesterone levels. These results suggest that NPY may play a direct role in control of gonadotropic ovarian hormonal levels