Parallel insulin-like actions of human growth hormone and its part sequence hGH 7-13.
The insulin-like effects of human growth hormone and the synthetic part sequence, N alpha-acetyl-hGH 7-13, on glycogen synthase and phosphorylase have been compared in an in vivo system using 16--18-day-old rats. Both the hormone and its part sequences had similar effects, increasing muscle glycogen synthase a activity and decreasing liver phosphorylase a activity, without affecting phosphorylase activity in muscle or synthase activity in liver. Insulin had similar effects, but also increased liver synthase a activity. The effects of all three substances could be abolished by prior treatment of the animals with anti-insulin serum, showing that the effects of growth hormone and its part sequences were insulin-dependent. Both growth hormone and the synthetic peptide increased the binding of insulin to liver plasma membrane. It is concluded that the insulin-like activity of human growth hormone is associated with a region containing residues 7 to 13 of the hormone molecule, and that this activity is insulin-dependent. It is suggested that both growth hormone and the synthetic peptide produce insulin-like activity by enhancing the binding of circulating insulin to its receptor.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D006003:Glycogen / Q000378:metabolism*; D006006:Glycogen Synthase / Q000378:metabolism; D013006:Growth Hormone / Q000097:blood / Q000494:pharmacology* / Q000031:analogs & derivatives; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008112:Liver Glycogen / Q000378:metabolism; D009132:Muscles / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology*; D006005:Phosphorylases / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011972:Receptor, Insulin / Q000378:metabolism
D006063:Chorionic Gonadotropin; D007328:Insulin; D008112:Liver Glycogen; D010446:Peptide Fragments; C037767:N(alpha)-acetylsomatotropin (7-13); D013006:Growth Hormone; D006003:Glycogen; D006005:Phosphorylases; D006006:Glycogen Synthase; D011972:Receptor, Insulin