Mergl Z, Acs Z, Makara G B
Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest.
Life Sci. 1995;56(8):579-85. doi: 10.1016/0024-3205(94)00490-j.
The effect of factors influencing pituitary growth hormone secretion may be mediated by a combination of several intracellular mechanisms. The involvement of cyclic AMP (cAMP) in the GH stimulatory effect of tau-aminobutyric acid (GABA) and of growth hormone releasing hormone (GHRH) was studied in neonatal rat pituitaries. In the pituitaries of the newborn rats GH secretion was stimulated by forskolin and by isobutylmethylxantine (IBMX). GHRH but not GABA elevated pituitary cAMP concentration, whereas both drugs increased GH secretion from 2-day old pituitaries. IBMX did not augment the cAMP stimulating effect of GHRH in 2-day old, but potentiated it in older (7, 14 and 21-day old) pituitaries. The results indicate the presence of a functioning, but relatively immature intracellular signal transmission system in the 2-day old rat pituitary.
影响垂体生长激素分泌的因素的作用可能是由几种细胞内机制共同介导的。研究了环磷酸腺苷（cAMP）在新生大鼠垂体中对γ-氨基丁酸（GABA）和生长激素释放激素（GHRH）的生长激素刺激作用中的参与情况。在新生大鼠的垂体中，福斯高林和异丁基甲基黄嘌呤（IBMX）刺激生长激素分泌。GHRH而非GABA可提高垂体cAMP浓度，而两种药物均可增加2日龄垂体的生长激素分泌。IBMX在2日龄时并未增强GHRH对cAMP的刺激作用，但在较大（7、14和21日龄）的垂体中具有增强作用。结果表明，2日龄大鼠垂体中存在一个功能正常但相对不成熟的细胞内信号转导系统。
