Harvey S, Baidwan J S
Department of Physiology, University of Alberta, Edmonton, Canada.
J Mol Endocrinol. 1990 Feb;4(1):13-21. doi: 10.1677/jme.0.0040013.
Administration of ovine GH to immature domestic fowl blunted their subsequent GH response to thyrotrophin-releasing hormone (TRH), a GH secretagogue in birds. The in-vivo administration of GH also reduced the ability of radiolabelled TRH to bind to plasma membranes of the pituitary caudal lobe, in which GH cells predominate. These inhibitory effects of GH were mediated by extrapituitary actions, since GH had no direct inhibitory effects on TRH-induced GH release or on pituitary TRH binding in vitro. GH inhibition of GH secretion and TRH binding would not appear to be mediated by hypothalamic somatostatin (SRIF) or peripheral somatomedin (IGF-I), since SRIF and IGF-I had no direct effects in vitro.
向未成熟的家禽体内注射绵羊生长激素（GH）会减弱其随后对促甲状腺激素释放激素（TRH）（鸟类中的一种生长激素促分泌素）的生长激素反应。生长激素的体内给药还降低了放射性标记的促甲状腺激素释放激素与垂体尾叶质膜结合的能力，垂体尾叶中生长激素细胞占主导。生长激素的这些抑制作用是由垂体外作用介导的，因为生长激素在体外对促甲状腺激素释放激素诱导的生长激素释放或垂体促甲状腺激素释放激素结合没有直接抑制作用。生长激素对生长激素分泌和促甲状腺激素释放激素结合的抑制作用似乎不是由下丘脑生长抑素（SRIF）或外周生长调节素（IGF-I）介导的，因为生长抑素和胰岛素样生长因子-I在体外没有直接作用。
