Serum deprivation affects secretory activity of cultured porcine ovarian follicles and granulosa cells and their response to hormones

The aim of the present study is to understand the hormonal mechanisms of the effect of malnutrition on ovarian follicle functions. For this purpose, we examined the effect of malnutrition/serum deprivation, addition of metabolic hormones and gonadotropin (IGF-I, leptin and FSH) and their combination on the release of progesterone (P4), testosterone (T), estradiol (E2) and insulin-like growth factor I (IGF-I) by cultured whole ovarian follicles and on P4 and IGF-I output by cultured granulosa cells isolated from porcine ovaries. It was observed that in ovarian follicles cultured with nutrients/serum addition of IGF-I reduced release of P4, but not of T or E2. Exogenous leptin reduced output of E2, but not of P4 or T, and increased IGF-I output. No significant effect of FSH on release of steroid hormones by isolated follicles was found. Serum deprivation did not affect release of P4, but reduced output of T and E2, and promoted IGF-I release by cultured ovarian follicles. Addition of hormones failed to prevent the effect of malnutrition on the secretory activity of cultured ovarian follicles. In cultured granulose cells, all the tested hormones promoted release of both P4 and IGF-I. Food restriction/serum deprivation reduced both P4 and IGF-I output. Additions of either IGF-I, leptin and FSH prevented the inhibitory action of malnutrition on both P4 and IGF-I release. The present observations (1) confirm the involvement of the hormones IGF-I, leptin and FSH in the control of secretory activity of ovarian cells, (2) demonstrate, that both isolated ovarian granulosa cells and whole follicles cultured in the absence of serum nutrients could be an adequate in-vitro model for studying the effect of malnutrition on ovarian secretory functions, and (3) suggest, that malnutrition could affect ovarian functions through changes in the release of ovarian hormones.