Selective suppression of insulin-induced proliferation of cultured human hepatoma cells by somatostatin.
The effects of somatostatin (SRIF), insulin, and triiodothyronine (T3) on the growth of human hepatoma cells were investigated on the well-differentiated human hepatoma cell line Hep3B. Results showed that both insulin and T3 can stimulate cell growth of serum starved Hep3B cells at physiological concentrations. SRIF alone showed little growth-promoting activity. When added concurrently with insulin, however, SRIF suppressed the insulin-induced cell proliferation in a dose-dependent manner. On the other hand, SRIF had no inhibitory effect on T3-induced cell proliferation. SRIF is labile in the medium, with a half-life of about 2 h during culture incubation. SRIF did not disturb the insulin binding to its surface receptors nor inhibit the insulin-dependent receptor kinase activity of Hep3B cells in vitro. These results suggest that postreceptor regulation may be involved. The selective suppression by SRIF of insulin-induced cell growth provides an unique approach to the study of insulin actions on proliferation of human hepatoma cells.
D006528:Carcinoma, Hepatocellular / Q000473:pathology; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007328:Insulin / Q000378:metabolism / Q000494:pharmacology*; D007329:Insulin Antagonists; D008099:Liver / Q000166:cytology*; D008113:Liver Neoplasms; D010766:Phosphorylation; D011972:Receptor, Insulin / Q000378:metabolism; D013004:Somatostatin / Q000494:pharmacology*; D013997:Time Factors; D014284:Triiodothyronine / Q000494:pharmacology
D007328:Insulin; D007329:Insulin Antagonists; D014284:Triiodothyronine; D013004:Somatostatin; D011972:Receptor, Insulin