Regulation of growth hormone secretion and action in amphibians and reptiles

Recent studies show that the structure and function of growth hormone (GK) is highly conserved among vertebrate species including the amphibians and reptiles. GH stimulates growth of adult structures and its growth-promoting effects are largely mediated through the somatomedins (insulin-like growth factors -IGF). Hypothalamic regulation of GH secretion in herpetofauna is generally less specific than in mammals, a situation that is also found in fishes and birds. Production of GH in herpetofauna is regulated by thyroid hormones, but the regulation (largely inhibitory) resembles the situation in birds more than mammals.