title: 1,2-Diacylglycerol and phorbol ester inhibit agonist-induced formation of inositol phosphates in human platelets: possible implications for negative feedback regulation of inositol phospholipid hydrolysis.
abstract: The present study has demonstrated that pretreatment of human platelets with either phorbol ester or 1,2-diacylglycerol inhibits agonist-induced formation of inositol phosphates; this inhibition can be correlated with a decrease in the release of ATP and 5-hydroxytryptamine by thrombin. The mechanism of this action is not known, but a role for protein kinase C is suggested, as both phorbol ester and 1,2-diacylglycerol have in common the ability to activate this enzyme. These results have important implications as a possible negative feedback control over agonist-induced hydrolysis of inositol phospholipids.
authors.forename: S P
authors.initials: SP
authors.lastname: Watson
authors.forename: E G
authors.initials: EG
authors.lastname: Lapetina
mesh_terms: D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D004075:Diglycerides / Q000494:pharmacology*; D005246:Feedback; D005989:Glycerides / Q000494:pharmacology*; D006801:Humans; D006868:Hydrolysis; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000097:blood*; D007700:Kinetics; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology*; D010704:Phorbols / Q000494:pharmacology*; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000097:blood; D013403:Sugar Phosphates / Q000097:blood*; D013917:Thrombin / Q000494:pharmacology
chemical_list: D004075:Diglycerides; D005989:Glycerides; D007295:Inositol Phosphates; D010703:Phorbol Esters; D010704:Phorbols; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D013403:Sugar Phosphates; C037178:phosphatidylinositol 4-phosphate; D015240:Phorbol 12,13-Dibutyrate; C038237:1-oleoyl-2-acetylglycerol; D013917:Thrombin