Insulin efficiently stores triglycerides in adipocytes by inhibiting lipolysis and repressing PGC-1alpha induction.

White adipose tissue (WAT) is important as an energy reservoir in mammals, but the precise mechanism by which energy storage in WAT is controlled remains unclear. It is well known that representative anabolic hormone insulin efficiently stores triglyceride in adipocytes. We showed that insulin inhibited beta-agonist-induced lipolysis at least in part by inhibiting phosphorylation of perilipin and hormone-sensitive lipase (HSL) in 3T3-L1 adipocytes. Furthermore, insulin inhibited beta-agonist-induced increase of PGC-1alpha expression, which is important for mitochondrial biogenesis and energy expenditure. These results suggest the possibility that insulin efficiently stores triglyceride in adipocytes by decreasing lipolysis and repressing energy expenditure.