ACTIVITY OF GROWTH-HORMONE PEPTIDES BGH-96-133 AND HGH-95-133 IN 3T3-F442A CELLS

Chemically synthesized bovine growth hormone (bGH) bGH 96-133 and its human homologue, hGH 95-133, have similar in vitro biological activiti es. Unlike native GH, bGH 96-133 and hGH 95-133 were completely withou t adipogenic or anti-insulin activity at doses up to 10 mu M. bGH 96-1 33 had insulin-like activity, with a 100% increase in glucose uptake a t 10 mu M. bGH was anti-mitogenic and bGH 96-133 and hGH 95-133 were m itogenic (EC(50) similar to 180 nM and maximal response at 1-2 mu M). Only bGH 96-133 and hGH 95-133 displaced [I-125]hGH 95-133 binding fro m 3T3-F442A fibroblasts with a K-d between 60-120 nM. bGH, hGH, insuli n and IGF-I were without effect on [I-125]hGH 95-133 binding. bGH 96-1 33 and hGH 95-133 did not significantly inhibit [125(I)]hGH Or [I-125] IGF-I binding. These experiments indicate that GH containing peptides bGH 96-133 and hGH 95-133 have mitogenic and insulin-like activity wit hout the adipogenic, anti-insulin or anti-mitogenic activity of bGH. T hese peptides have a specific binding site which appears to be distinc t from the GH, insulin and IGF-I receptors.