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生长激素(GH)对不同组织中的氨基酸转运和蛋白质合成有急性兴奋作用,但这些效应是生长激素的促生长作用还是独立的胰岛素样的作用,至令没有得到证实。与天然的人生长激素(22K hGH)相比,分子量为20000道尔顿人生长激素的变异体(20K hGH)的促生长活性与胰岛素样活性的比值很高,因此,它可作为探讨上述问题的工具。作者用雌性去垂体大鼠离体的膈肌进行实验,比较天然22K hGH 与变异体20K hGH 刺激氨基酸转运与蛋白质合成的相对活性。将一对完整的偏侧膈在不同浓度的22K hGH 或20K hGH存在或缺如的情况下预先孵育1h,在孵育的最后1h 内,在孵育液中加~(14)C 标记的3-氧-甲基葡萄糖,以测定 hGH 在糖转运中的胰岛素样活性,同肘亦加入~3H 标记的α-氨基异丁酸或~3H 标记的苯丙氨酸,分别
Growth hormone (GH) has acute effects on amino acid transport and protein synthesis in different tissues, but whether these effects are growth-promoting or independent insulin-like effects has not been demonstrated. Compared with natural human growth hormone (22K hGH), the ratio of the growth promoting protein to insulin-like activity of a mutant with a molecular weight of 20,000 Dalton human growth hormone (20K hGH) is very high, so it can be used as a probe into the above problems Tool of. In this study, we performed experiments on the isolated diaphragm of female pituitary gland to compare the relative activity of natural 22K hGH with the variant 20K hGH in stimulating amino acid transport and protein synthesis. A pair of intact diaphragms were preincubated for 1 h in the presence or absence of various concentrations of 22K hGH or 20K hGH. During the last 1 h of incubation, ~ (14) C-labeled 3- -methylglucose to determine the insulin-like activity of hGH during sugar transport, with ~ 3H labeled alpha-aminoisobutyric acid or ~ 3H-labeled phenylalanine added to the elbow, respectively