WORTMANNIN, A SPECIFIC PHOSPHATIDYLINOSITOL 3-KINASE INHIBITOR, INHIBITS ADIPOCYTIC DIFFERENTIATION OF 3T3-L1 CELLS

The effect of wortmannin, which inhibits phosphatidylinositol 3-kinase (PI 3-kinase), on adipocytic differentiation of 3T3-L1 cells was exam ined. The extent of differentiation was evaluated by the staining of a dipocytes with Oil Red O and measurement of glycerol 3-phosphate dehyd rogenase (GPDH) activity. Wortmannin, at over 100 nM, significantly in hibited adipogenesis of cells treated with isobutyl-methylxanthine, de xamethasone, and insulin with an IC50 value about 50 nM. These results suggest that PI 3-kinase plays a role in adipocytic differentiation o f 3T3-L1 cells. (C) 1995 Academic Press, Inc.