Melner M H, Young S L, Czerwiec F S, Lyn D, Puett D, Roberts J L, Koos R D
Endocrinology. 1986 Nov;119(5):2082-8. doi: 10.1210/endo-119-5-2082.
We have previously demonstrated the presence of proopiomelanocortin (POMC) messenger RNA (mRNA) in rat granulosa cells. This study examines the unique, tissue-specific regulation of granulosa cell POMC mRNA levels by hormones with established regulatory effects on these cells. Northern blot analysis of immature rat ovarian RNA revealed the presence of a single mRNA of approximately 900 base pairs in length. The levels of ovarian POMC mRNA increased approximately 6-fold 48 h after priming with PMSG when expressed per microgram of total RNA. Granulosa cells were isolated from immature PMSG-primed rats and cultured under serum-free conditions in the presence and absence of various hormones to determine their effect on POMC mRNA levels. Treatment of the cells for 48 h with LH (100 ng/ml), androstenedione (10(-7) M), or LH plus androstenedione elevated POMC mRNA levels. LH alone elicited a 5-fold increase in POMC mRNA, and androstenedione elicited a 10-fold increase; the combination treatment led to a 47-fold increase. The effects of the nonaromatizable androgen dihydrotestosterone (DHT) were also evaluated. Treatment for 48 h with DHT (10(-7) M) elicited a 40-fold increase in POMC mRNA levels. In vivo experiments measuring ovarian POMC mRNA from immature female rats corroborated the in vitro results. Animals injected sc with DHT (500 micrograms) demonstrated 5-fold increases in ovarian POMC mRNA when expressed per microgram of total RNA. These studies provide both in vitro and in vivo evidence that granulosa cell POMC mRNA is under unique hormonal regulation by both androgens and gonadotropins.
我们先前已证明大鼠颗粒细胞中存在阿黑皮素原（POMC）信使核糖核酸（mRNA）。本研究探讨了对这些细胞具有既定调节作用的激素对颗粒细胞POMC mRNA水平的独特组织特异性调节。对未成熟大鼠卵巢RNA进行的Northern印迹分析显示存在一种长度约为900个碱基对的单一mRNA。当以每微克总RNA表示时，用孕马血清促性腺激素（PMSG）预处理48小时后，卵巢POMC mRNA水平增加了约6倍。从未成熟的经PMSG预处理的大鼠中分离出颗粒细胞，并在有无各种激素的无血清条件下培养，以确定它们对POMC mRNA水平的影响。用促黄体生成素（LH，100 ng/ml）、雄烯二酮（10⁻⁷ M）或LH加雄烯二酮处理细胞48小时可提高POMC mRNA水平。单独使用LH可使POMC mRNA增加5倍，雄烯二酮可使其增加10倍；联合处理导致增加47倍。还评估了不可芳香化雄激素双氢睾酮（DHT）的作用。用DHT（10⁻⁷ M）处理48小时可使POMC mRNA水平增加40倍。在未成熟雌性大鼠中测量卵巢POMC mRNA的体内实验证实了体外实验结果。皮下注射DHT（500微克）的动物，以每微克总RNA表示时，卵巢POMC mRNA增加了5倍。这些研究提供了体外和体内证据，表明颗粒细胞POMC mRNA受到雄激素和促性腺激素的独特激素调节。
