Insulin and somatomedins A and B: Comparison of biological activities in cultured human skin-derived fibroblasts

Abstract

The responsiveness of cultured human skin-derived fibroblasts to insulin and to somatomedins-A and -B (stimulation of thymidine incorporation and alpha-aminoisobutyrate (AIB) uptake) was examined. Under selected conditions, insulin stimulates both AIB uptake and thymidine incorporation, whereas somatomedin-A stimulates only AIB uptake; under the same conditions, somatomedin-B stimulates neither process. On the basis of the different spectra of biological activities observed for the three polypeptides it is suggested that the receptor for insulin in cultured human fibroblasts is independent from the ones for the somatomedins.