Phospholipase A2 is a differentiation-dependent enzymatic activity for adipogenic cell line and adipocyte precursors in primary culture

Phospholipase A2 enzymatic activity was measured in the teratoma-derived adipogenic cell line 1246 and in adipocyte precursors in primary cultures. It was shown that enzymatic activity was low while the cells were undifferentiated and increased by 20-24-fold after the cells had undergone adipocyte differentiation. The increase of phospholipase A2 activity follows the same time course as that observed for glycerol-3-phosphate dehydrogenase activity used as a marker of differentiation. In contrast, the differentiation-deficient, insulin-independent cell line 1246-3A always contained very low levels of phospholipase A2 activity. Phospholipase A2 activity measured in the 1246 cells was inhibited in a dose-dependent fashion by incubation with ONO-RS-082 and quinacrine which are inhibitors of phospholipase A2 activity. Measurements of arachidonate metabolites in 1246 cells showed that production of prostaglandin F2 alpha by the 1246 cells followed the same time course as the increase of phospholipase A2 activity during differentiation. Similar results were obtained with primary cultures of adipocyte precursors. These results indicate that phospholipase A2 is a differentiation-dependent enzymatic activity for the adipogenic cell line 1246 and for adipocyte precursors in primary culture. These data suggest that metabolic pathways controlled by phospholipase A2 activity could play an important physiological role in adipose tissue differentiation.