Insulin and fatty acids regulate the expression of the fat droplet-associated protein adipophilin in primary human trophoblasts

Objective: This study was undertaken to test the hypothesis that insulin and fatty acids regulate adipophilin expression in cultured human trophoblasts. Study design: Cytotrophoblasts isolated from term human placentas were cultured in the absence or presence of insulin (10 nmol/L), and a mix of oleic and linoleic acid in serum-free medium. The expression of adipophilin as well as the fatty acid transport proteins (FATP) 2, 3, 4 and 6 was examined. Fat accumulation was quantified by BODIPY staining and fat uptake determined using [³H]-oleic acid. Results: A combination of insulin and fatty acids enhanced the expression of adipophilin (2.3-fold, P < .05). In contrast, the expression of FATPs was unchanged. Furthermore, insulin and fatty acids increased the accumulation of fat droplets in trophoblasts by 4- to 5-fold (P < .05), but had no effect on oleic acid uptake. Conclusion: Insulin and fatty acids enhance the expression of adipophilin and the formation of fatty acid droplets in term human trophoblasts.