title: The effects of forskolin on adenylate cyclase in S49 wild type and cyc- cells.
abstract: The effect of forskolin on adenylate cyclase in S49 wild type and cyc- cells was tested. Forskolin stimulated adenylate cyclase activity in cyc- membranes, particularly with Mn++ as cofactor. Forskolin stimulation of adenylate cyclase in wild type membranes was greater than in cyc- membranes, and the ability of forskolin to stimulate cyc- membranes was enhanced by Lubrol PX extracts of human erythrocyte membranes. Compared to its potent effect on intact wild type cells, forskolin was a poor stimulator of cAMP accumulation in cyc- cells. Cyc- cells proliferated in medium containing forskolin, while the growth of wild type cells in such medium was inhibited and the wild type cells ultimately died. Clones selected from a suspension of wild type cells on the basis of forskolin resistance showed the characteristics of cyc- cells. Thus, forskolin does not substantially activate adenylate cyclase activity in intact cyc- cells. Our data indicate that the guanine nucleotide regulatory protein (G/F) enhances forskolin activation of adenylate cyclase.
mesh_terms: D000262:Adenylyl Cyclases / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D005576:Colforsin; D004224:Diterpenes / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D066298:In Vitro Techniques; D013997:Time Factors
chemical_list: D004224:Diterpenes; D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D000262:Adenylyl Cyclases