Work

5′-CMP stimulates phospholipase A-mediated hydrolysis of phosphatidylinositol in permeabilized pituitary GH3 cells

Year: 1991

Type: article

Abstract: We showed previously that 5'-CMP activates PtdIns-Ins base exchange and reversal PtdIns synthase in permeabilized rat pituitary GH3 cells. Here we report another effect of 5'-CMP on PtdIns metabolism in these cells. In permeabilized GH3 cells prelabelled with [3H]Ins and incubated in buffer with LiCl and a free Ca2+ concentration of 0.1 microM but without added Ins, 5'-CMP stimulated formation of glycerophospho[3H]inositol (GroP[3H]Ins) after a lag period of at least 5 min. This effect was concentration-dependent; the apparent Km was 0.30 +/- 0.02 mM. CDP and CTP stimulated GroPIns formation less effectively than did 5'-CMP, but cytidine, 2'-CMP, 3'-CMP, 5'-AMP and 5'-GMP had no effect. 5'-CMP stimulated formation of lysoPtdIns also. In permeabilized GH3 cells prelabelled with [3H]arachidonic acid, 5'-CMP stimulated release of [3H]arachidonic acid without a measurable lag period. These data show that 5'-CMP stimulates a phospholipase A activity in permeabilized GH3 cells that hydrolyses PtdIns.

Source: Biochemical Journal

DOI: 10.1042/bj2780831

Authors: A B Cubitt, C N Thaw, M C Gershengorn

Institution: Cornell University

Language: English

Topic: Lipid metabolism and biosynthesis

Subfield: Biochemistry

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: bronze

Funders: National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases

Awards: THYROTROPIN RELEASING HORMONE ACTION IN PITUITARY CELLS, G4699254760