title: Phorbol ester inhibition of the hormone-stimulated phosphoinositide cycle in WRK-1 cells.
abstract: WRK-1 rat mammary tumour cells respond to vasopressin with increased accumulation of inositol phosphates as well as increased precursor incorporation into phosphatidylinositol. The phorbol ester, phorbol 13-myristate 12-acetate (PMA) inhibits by 80% both inositol phosphate accumulation and increased precursor incorporation. This inhibition is much less evident at early times (2 min) than at later times (25 min). The vasopressin-induced rise in cytosolic free Ca2+ is inhibited in a similar manner. Oleoylacetylglycerol is inactive with respect to inhibition of vasopressin-induced increases in incorporation of 32P into phosphoinositides. PMA has no effect on vasopressin binding at saturating concentrations of the hormone and does not affect the binding affinity.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004075:Diglycerides / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D008325:Mammary Neoplasms, Experimental / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D010712:Phosphatidic Acids / Q000378:metabolism*; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014667:Vasopressins / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D004075:Diglycerides; D007295:Inositol Phosphates; D010710:Phosphates; D010712:Phosphatidic Acids; D014667:Vasopressins; C038237:1-oleoyl-2-acetylglycerol; D000255:Adenosine Triphosphate; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium