人生长激素和转移的人生长激素基因对去垂体鱼的生长代偿效应

THE GROWTH REPLACEMENT OF HYPOPHYSECTOMIZED FISH BY HUMAN GROWTH HORMONE AND THE CORRESPONDING TRANSGENE

通过显微注射技术,将小鼠重金属螯合蛋白(MT-1)基因启动顺序与人生长激素基因顺序的重组体pMThGH注入鲤鱼(Cyprinus carpio)的受精卵内,由此发育的转基因鱼及其后代F1和F2均显示出快速生长效应。去垂体后,转基因鲤鱼F2持续生长,而非转基因鲤鱼和鲫鱼(Carassius auratus)的生长停止。给去垂体的鲫鱼腹腔注射生物合成的人生长激素(hGH),可恢复其生长。实验结果表明,转基因鱼体内表达和体外生物合成的hGH均能代偿鲤鱼和鲫鱼的内源生长激素并刺激去垂体鱼的生长。

Transgenic common carp (Cyprinus carpio) have been produced by microinjecting a construct pMThGH, a human growth hormone (hGH) gene with a mouse metallothionein-1 (MT) gene promoter in pBR322, into fertilized eggs. The transgenic fish and the descendent generation F1 and F2 have exhibited growth enhancement. After hypophysectomy, the growth of the pMThGH-transgenic F2 common carp continued while the growth of control fish, including non-transgenic common carp and crucian carp (Carassius auratus), ceased. This cessation in crucian carp could be overcome by subcutaneous injection of recombinant hGH. It has therefore been demonstrated that hGH, both from the transgene expression in vivo and from biosynthetic source via subcutaneous injection, can replace the carp's endogenous growth hormone to stimulate the growth rate following hypophysectomy.