The involvement of the mTOR system/enzyme sirtuin 1 (SIRT1) intracellular signaling system in the control of ovarian functions and its role in mediating hormonal action on the ovary has been proposed, but this hypothesis should be supported by a demonstrated influence of hormones on mTOR/SIRT1. Therefore, the aim of our in vitro experiments was to examine the effect of the known hormonal regulators of ovarian functions, such as follicle-stimulating hormone (FSH), oxytocin (OT) and insulin-like growth factor I (IGF-I), on mTOR/SIRT1. The accumulation of SIRT1 in porcine ovarian granulosa cells cultured with and without these hormones (at doses of 1, 10 or 100 ng.ml-1 ) was evaluated using immunocytochemistry. It was observed that the addition of FSH (at 10 ng.ml-1 but not at 1 or 100 ng/ml) and OT (at all tested doses) increased the expression of SIRT1 in ovarian cells. In addition, 100 ng.ml-1 , but not at 1 or 10 ng.ml-1 , of IGF-I decreased SIRT1 accumulation. Our observations are the first demonstration that hormones can directly regulate the ovarian mTOR/SIRT1 system and that this system could mediate the action of hormonal regulators on the ovary.
The aim of present studies was to examine the interrelationships between reproductive events, age, body mass and steroid hormones in roe deer females (Capreolus capreolus). For this purpose we compared seasonal changes in body mass, blood levels of progesterone and estradiol (1) in young (1 year) and adult (2-4 years old) does and (2) in pregnant and non-pregnant animals. Monthly during 12 months all animals were weighed, blood plasma was collected, and concentration of progesterone and estradiol was analysed by RIA. Pregnant animals had significantly higher body weight, than non-pregnant ones, in November (before foetus implantation), and lower body weight in comparison with non-pregnant females in August (after parturition). In non-pregnant females high level of progesterone was observed from August (mating) up to December. Thereafter progesterone level declined up to minimum in summer months (April-July). Pregnant animals had increased progesterone level from February (foetus implantation) up to June (time after labour). In non-pregnant females, three peaks of estradiol concentration were observed in October, December and May. Pregnant animals, in contrast to non-pregnant females, had spring (January-March) gravidity-associated peak of estradiol level, but absence of summer (May) peak before parturition. Comparison of annual changes in body weight and plasma steroid hormone level in pregnant yearlings and old animals, as well as the number of offspring in these animals did not show principal age-dependent differences in these indexes, although yearlings had higher absolute progesterone (in December) and estradiol (in October and November) level than old animals. Our observations suggest significant seasonal changes in plasma progesterone and estradiol level and body weight in this species. Substantial differences in these changes in pregnant and non-pregnant animals demonstrate the involvement of steroid hormones in control of pregnancy in roe deer does. The absence of age-dependent differences in body weight and fecundity rate do not confirm previous hypothesis that age-dependent differences in metabolism and body mass can reduce fertility rate in yearlings. Moreover, our observations are the first demonstration of higher rate of steroidogenesis in young animals, than in adult females during early stages of gravidity and before embryo implantation. It is not to be excluded, that age-dependent reduction in ovarian steroid hormones level could be a cause of future infertility in old animals.
The action of the medicinal plant Tribulus terrestris (TT) on bovine ovarian cell functions, as well as the protective potential of TT against xylene (X) action, remain unknown. The aim of the present in vitro study was to elucidate the influence of TT, X and their combination on basic bovine ovarian cell functions. For this purpose, we examined the effect of TT (at doses of 0, 1, 10, and 100 ng/ml), X (at 20 μg/ml) and the combination of TT + X (at these doses) on proliferation, apoptosis and hormone release by cultured bovine ovarian granulosa cells. Markers of proliferation (accumulation of PCNA), apoptosis (accumulation of Bax) and the release of hormones (progesterone, testosterone and insulin-like growth factor I, IGF-I) were analyzed by quantitative immunocytochemistry and RIA, respectively. TT addition was able to stimulate proliferation and testosterone release and inhibit apoptosis and progesterone output. The addition of X alone stimulated proliferation, apoptosis and IGF-I release and inhibited progesterone and testosterone release by ovarian cells. TT was able to modify X effects: it prevented the antiproliferative effect of X, induced the proapoptotic action of X, and promoted X action on progesterone but not testosterone or IGF-I release. Taken together, our observations represent the first demonstration that TT can be a promoter of ovarian cell functions (a stimulator of proliferation and a suppressor of apoptosis) and a regulator of ovarian steroidogenesis. X can increase ovarian cell proliferation and IGF-I release and inhibit ovarian steroidogenesis. These effects could explain its antireproductive and cancer actions. The ability of TT to modify X action on proliferation and apoptosis indicates that TT might be a natural protector against some ovarian cell disorders associated with X action on proliferation and apoptosis, but it can also promote its adverse effects on progesterone release.
Tribulus terrestris, L. (puncture vine) have been used as a folk medicine for five thousands of years, but its targets, effects, their mechanisms and application requires further studies. This paper reviews the provenance, constituents and properties of Tribulus terrestris, L., its general physiological and health effects, as well as the currently available knowledge concerning its influence on male and female reproductive processes and their dysfunctions. Analysis of the available publications demonstrated the influence of Tribulus terrestris on a wide spectrum of targets and physiological processe and disorders. In particular, Tribulus terrestris can be a stimulator of male and female reproductive processes at the level of central nervous system, sexual behaviour, pituitary and gonadal hormones and their receptors, gonadal functions (including ovarian follicullogenesis and spermatogenesis), improvement of the quality and quantity of gametes (at least of sperm) and fecundity. This ability of puncture vine is applicable for the improvement of man’s sexual desire and sperm quality in vivo and in vitro, as well as of women’s libido, activation of women’s reproductive organs, fecundity, and treatment of infertility, especially that related to the polycystic ovarian syndrome.