Gitay-Goren H, Lindenbaum E S, Kraiem Z
Endocrine Research Unit, Carmel Hospital, Haifa, Israel.
Mol Cell Endocrinol. 1989 Aug;65(1-2):195-201. doi: 10.1016/0303-7207(89)90180-9.
The effects of prolactin (PRL), alone and as a modulator of human chorionic gonadotropin (hCG) action, on steroidogenesis and cAMP accumulation in rat luteal cell cultures were examined. Cultured rat luteal cells were prepared from immature rats primed with pregnant mare serum gonadotropin and hCG. In vitro treatment was performed with 0.1 and 0.2 IU/ml hCG and 1-100 ng/ml PRL. Cultures were incubated for 48 h for evaluation of progesterone (P4) secretion and for 1 h for measurement of cAMP accumulation. The same doses of hormones and incubation periods were also used in preovulatory rat granulosa cell cultures and found to cause a significant, dose-dependent inhibition in estradiol, P4 and cAMP accumulation. In luteal cell cultures, on the other hand, P4 secretion was significantly elevated, in a dose-dependent manner, by PRL. Moreover, identical doses of PRL caused a significant, dose-dependent stimulation of cAMP accumulation. Basal levels of P4 were also significantly elevated by PRL alone, but no such stimulation by PRL was detected in basal levels of cAMP. Addition of the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine, increased the stimulation of P4 and cAMP by hCG + PRL in a manner dependent on PRL concentrations. The overall data therefore demonstrate divergent effects of PRL on cAMP accumulation and steroidogenesis in the ovary: inhibitory in the preovulatory and stimulatory in the postovulatory state. Moreover, these findings suggest a possible common mechanism linking the effects of PRL before and after ovulation: inhibition of cAMP accumulation via enhanced breakdown of the nucleotide.
研究了催乳素（PRL）单独作用以及作为人绒毛膜促性腺激素（hCG）作用调节剂时，对大鼠黄体细胞培养物中类固醇生成和环磷酸腺苷（cAMP）积累的影响。培养的大鼠黄体细胞取自用孕马血清促性腺激素和hCG预处理的未成熟大鼠。体外实验使用0.1和0.2 IU/ml的hCG以及1 - 100 ng/ml的PRL进行处理。培养物孵育48小时以评估孕酮（P4）分泌，孵育1小时以测量cAMP积累。相同剂量的激素和孵育时间也用于排卵前大鼠颗粒细胞培养，发现会导致雌二醇、P4和cAMP积累受到显著的剂量依赖性抑制。另一方面，在黄体细胞培养物中，PRL以剂量依赖性方式显著提高了P4分泌。此外，相同剂量的PRL对cAMP积累产生了显著的剂量依赖性刺激。单独使用PRL也显著提高了P4的基础水平，但在cAMP基础水平未检测到PRL的这种刺激作用。添加磷酸二酯酶抑制剂3 - 异丁基 - 1 - 甲基黄嘌呤，以依赖于PRL浓度的方式增强了hCG + PRL对P4和cAMP的刺激作用。因此，总体数据表明PRL对卵巢中cAMP积累和类固醇生成具有不同的作用：在排卵前具有抑制作用，在排卵后具有刺激作用。此外，这些发现提示了一种可能的共同机制，将排卵前后PRL的作用联系起来：通过增强核苷酸的分解来抑制cAMP积累。
