Navickis R J, Jones P B, Hsueh A J
Mol Cell Endocrinol. 1982 Jun;27(1):77-88. doi: 10.1016/0303-7207(82)90064-8.
The hormonal modulation of prolactin (PRL)-binding capacity of rat granulosa cells was studied. Granulosa cells obtained from immature, hypophysectomized, estrogen-treated rats were cultured for 2 days in a serum-free medium in the presence of various hormones. FSH treatment in vitro stimulated granulosa cell PRL-binding capacity by approximately 4-6-fold in a dose-dependent manner. Concomitant treatment with 10-8 M GnRH inhibited the FSH-induced increase in PRL-binding capacity by 64%. In contrast, the inhibitory effect of GnRH was blocked by concomitant treatment with 10-6 M of a GNRH antagonists, [D-pGlu1, D-Phe2, D-Trp3,6]GnRH. PRL-binding capacity was also increased (approximately 2-fold) by in vitro treatment with cholera toxin (10 microgram/ml). In granulosa cells pre-treated with FSH in vitro for 2 days, hCG treatment for 2 additional days stimulated PRL-binding capacity in a dose-dependent manner (approximately 2-fold). Likewise, treatment with LH (100 ng/ml) also stimulated PRL-binding capacity by approximately 2-fold. These in vitro studies demonstrated that gonadotropins (FSH, LH and hCG) directly enhanced PRL binding by granulosa cells, whereas GnRH inhibited FSH action.
