Effect of estrogen on triacylglycerol metabolism: Inhibition of post‐heparin plasma lipoprotein lipase by phosvitin, an estrogen‐induced protein

The effects of phosvitin and lipovittelin on partially purified postheparin plasma levels of lipoprotein lipase (LPL) and triacylglycerol (TGL) and adipose tissue LPL were studied in laying and nonlaying female turkeys and estrogen-treated male turkeys. Postheparin plasma lipolytic activities and those of LPL and TGL decreased 2- to 3-fold after the onset of egg production, while a 24-fold increase in triacylglycerol (TG) was observed. Lipovittelin had no effect on either TGL or LPL, while phosvitin, in a dose of 3 mcg protein/ml assay mixture, had a strong inhibitory effect on plasma LPL and chicken adipose tissue LPL. TGL was not affected by phosvitin. The results suggest that phosvitin may have a role in the regulation of adipose tissue and plasma levels of TG in laying birds.