title: Polyphosphoinositide hydrolysis by phospholipase C is accelerated by thyrotropin releasing hormone (TRH) in clonal rat pituitary cells (GH3 cells).
abstract: Thyrotropin releasing hormone (TRH) accelerates the turnover of phosphatidylinositol in GH3 cells ('phospholipid response'). From the analysis of inositol phosphates in the presence of Li+ which inhibits their dephosphorylation, it can be concluded that the hydrolysis of phosphatidylinositol 4,5-biphosphate, and possibly of phosphatidylinositol 4-phosphate by phospholipase C is markedly accelerated by TRH. It appears that this reaction initiates the acceleration of phosphatidylinositol turnover. The specificity of hormonally regulated phospholipase C reaction for polyphosphoinositides has important implications for the potential role of the phospholipid response as a mechanism of membrane signal transduction.
mesh_terms: D000818:Animals; D002460:Cell Line; D002712:Chlorides / Q000494:pharmacology; D006868:Hydrolysis; D007700:Kinetics; D008094:Lithium / Q000494:pharmacology; D018021:Lithium Chloride; D010716:Phosphatidylinositols / Q000378:metabolism*; D010740:Phospholipases / Q000378:metabolism*; D010911:Pituitary Neoplasms / Q000201:enzymology*; D051381:Rats; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D010738:Type C Phospholipases / Q000378:metabolism*
chemical_list: D002712:Chlorides; D010716:Phosphatidylinositols; D013973:Thyrotropin-Releasing Hormone; D008094:Lithium; D010740:Phospholipases; D010738:Type C Phospholipases; D018021:Lithium Chloride