Copeland K C, DeSouza M M, Gibson P C
Department of Pediatrics, University of Vermont College of Medicine, Burlington 05405.
Res Exp Med (Berl). 1990;190(2):137-43. doi: 10.1007/pl00020016.
Growth hormone (GH) secretion increases at the time of puberty, and both androgens and estrogens increase the GH response to provocative agents. Little is known, however, with regard to the mechanism or site of action of gonadal steroid-stimulated GH secretion. Using monolayer primary cell culture and radioimmunoassay techniques, insulin-like growth factor I (IGF-I), purified and biosynthetic human GH, 17 beta-estradiol (E2), and testosterone (T) effects on GH release from rat anterior pituitary cells were investigated. Media content of rat GH was measured, both basally and after growth hormone releasing factor (GRF) stimulation. IGF-I at 50 nM concentration inhibited basal rGH release but not in GRF-stimulated cells. E2 (10 pM) stimulated basal secretion of rGH, although higher concentrations did not. High concentrations of T (100,000 pM) caused an increase in GRF-stimulated rGH secretion. Neither purified nor biosynthetic hGH pretreatment influenced subsequent rGH release. These results suggest that IGF-I inhibits and E2 (low dose) and T (high dose) augment rGH release in part at the level of the anterior pituitary.
青春期时生长激素（GH）分泌增加，雄激素和雌激素均可增强GH对刺激剂的反应。然而，关于性腺类固醇刺激GH分泌的作用机制或作用部位，目前所知甚少。采用单层原代细胞培养和放射免疫分析技术，研究了胰岛素样生长因子I（IGF-I）、纯化及生物合成的人GH、17β-雌二醇（E2）和睾酮（T）对大鼠垂体前叶细胞GH释放的影响。测定基础状态下以及生长激素释放因子（GRF）刺激后大鼠GH的培养基含量。50 nM浓度的IGF-I抑制基础状态下的大鼠GH释放，但对GRF刺激的细胞无此作用。E2（10 pM）刺激基础状态下的大鼠GH分泌，更高浓度则无此作用。高浓度的T（100,000 pM）导致GRF刺激的大鼠GH分泌增加。纯化及生物合成的人GH预处理均不影响随后的大鼠GH释放。这些结果提示，IGF-I起抑制作用，而E2（低剂量）和T（高剂量）部分在前叶垂体水平增强大鼠GH释放。
