The objective of our study was to examine the influence of the plant polyphenol resveratrol (R) on the rapamycin signalling pathway (mammalian target of rapamycin; mTOR) and basic ovarian cell functions in mammalian targets, as well as on their response to the physiological hormonal stimulators follicle-stimulating hormone (FSH) and insulin-like growth factor I (IGF-I). Resveratrol was found to stimulate sirtuin 1 accumulation and apoptosis, inhibit proliferation, suppress P and promote T and E release. Alone, FSH promoted proliferation and had no effect on apoptosis, but had an inhibitory effect on these processes when combined with R. IGF-I alone stimulated proliferation and inhibited apoptosis and promoted P production but not that of T; however, in the presence of R, the addition of IGF-I switched from having an anti-apoptotic to a pro-apoptotic effect and stimulated T release, but it did not modify the effect of IGF-I on proliferation and P output. These observations: (1) demonstrate that R directly affects the basic ovarian cell functions of proliferation, apoptosis and steroidogenesis, (2) provide further evidence of the involvement of FSH and IGF-I in the regulation of these processes, (3) demonstrate the ability of R to prevent and even invert the effects of FSH and IGF-I on ovarian cells and (4) indicate that the effects of R may be mediated by the mTOR–sirtuin intracellular signalling system.
Localization and Quantification of Binding Sites for Follicle-Stimulating Hormone, Luteinizing Hormone, Growth Hormone, and Insulin-Like Growth Factor I in Sheep Ovarian Follicles1
