Effects of tumor promoters (mezerein, teleocidin and palytoxin) on growth hormone secretion from rat anterior pituitary cells cultured in monolayer.
The effects of compounds with tumor promoting activity (mezerein, teleocidin and palytoxin) on rat growth hormone (rGH) release was compared to that of TPA (12-O-tetradecanoyl phorbol-13-acetate). Mezerein and teleocidin both of which are activators of protein kinase C (TPA type tumor promoter), elicited rGH release about 3.5 to 4 fold above control values. The ED 50 was 16 nM for mezerein, 1.1 nM for teleocidin and 1.5 nM for TPA. In contrast to mezerein or teleocidin, a non-TPA type tumor promoter (palytoxin) which does not activate protein kinase C failed to stimulate rGH release. These observations suggest that the activation of protein kinase C is essential in the release of rGH induced by the tumor promoters.
D000178:Acrylamides; D000818:Animals; D002273:Carcinogens; D002478:Cells, Cultured; D003064:Cnidarian Venoms / Q000494:pharmacology*; D004224:Diterpenes; D004789:Enzyme Activation / Q000187:drug effects; D013006:Growth Hormone / Q000378:metabolism*; D008235:Lyngbya Toxins / Q000494:pharmacology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013729:Terpenes / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D000095702:Polyether Toxins
D000178:Acrylamides; D002273:Carcinogens; D003064:Cnidarian Venoms; D004224:Diterpenes; D013006:Growth Hormone; D008235:Lyngbya Toxins; D011493:Protein Kinase C; D013729:Terpenes; D013755:Tetradecanoylphorbol Acetate; C022176:teleocidins; C011309:mezerein; C010272:palytoxin; D000095702:Polyether Toxins