Angiotensin II increases lipogenesis in 3T3-L1 and human adipose cells

Abstract

Angiotensin II (Ang II) is one of numerous hormones recently shown to be synthesized and secreted by adipose cells. Although the function of Ang II in adipose tissue is unknown, several studies indirectly suggest that it may be involved in control of adiposity. Little is known, however, about direct actions of Ang II in adipose cells. To further investigate this issue, we first characterized the type of Ang II receptors in 3T3-L1 adipocytes. We then tested the hypothesis that Ang II exerted direct actions on adipocyte metabolism using both 3T3-L1 and human adipocyte models. We report here that Ang II significantly increased triglyceride content and the activities of two key lipogenic enzymes (fatty acid synthase, FAS and glycerol-3-phosphate dehydrogenase, GPDH) in 3T3-L1 adipocytes, and that these effects were mediated through the type-2 Ang II receptor. We also report that Ang II exerted similar effects in human adipose cells maintained in primary culture. Finally, we demonstrate that Ang II increased the transcription rate of the FAS and ob genes in 3T3-L1 and human adipose cells. These results indicate that Ang II may be involved in control of adiposity through regulation of lipid synthesis and storage in adipocytes.