ACTH stimulates turnover of the phosphatidylinositol-glycan.
Primary cultures of calf adrenal glomerulosa cells were prelabeled for 3 days with [3H]inositol or [3H]glucosamine and stimulated with 10 nM ACTH. Labeled phosphatidylinositol (PI), polyphosphoinositides (PIP and PIP2) and a novel phosphatidylinositol-glycan (PI-glycan) were measured after separation by TLC. [3H]-Inositol labeling of PI, PIP and PIP2 increased rapidly, whereas labeling of the PI-glycan showed an initial decrease at 1 minute followed by a subsequent increase. Similar results were obtained when cells were prelabeled with [3H]glucosamine, viz. the PI-glycan label decreased at 1 min and subsequently increased. These results suggest that ACTH provokes (a) coordinated increases in the synthesis of PI, PIP, PIP2 and the PI-glycan, and (b) the increase in PI-glycan synthesis is preceded by initial decrease, presumably reflecting hydrolysis of this lipid.
Cozza
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EN
Departament of Internal Medicine, College of Medicine, University of South Florida, Tampa.
Vila
M C
MC
Gomez-Sanchez
C E
CE
Farese
R V
RV
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D005944:Glucosamine / Q000378:metabolism; D017261:Glycosylphosphatidylinositols; D066298:In Vitro Techniques; D010716:Phosphatidylinositols / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism*; D015384:Zona Glomerulosa / Q000187:drug effects / Q000378:metabolism*
D017261:Glycosylphosphatidylinositols; D010716:Phosphatidylinositols; D011134:Polysaccharides; D000324:Adrenocorticotropic Hormone; D005944:Glucosamine