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Palmitoleic acid (n-7) increases white adipocyte lipolysis and lipases content in a PPAR{alpha} dependent manner

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AJP Endocrinology and Metabolism

Published online on

Abstract

Here we investigated whether palmitoleic acid, a fatty acid that enhances whole body glucose disposal and suppresses hepatic steatosis, modulates triacylglycerol (TAG) metabolism in adipocytes. For this, both differentiated 3T3-L1 cells treated with either palmitoleic acid (16:1n7, 200 µM) or palmitic acid (16:0, 200 µM) for 24h and primary adipocytes from wild type or PPARα deficient mice treated with 16:1n7 (300 mg/kg/day) or oleic acid (18:1n9, 300 mg/kg/day) by gavage for 10 days were evaluated for lipolysis, TAG and glycerol 3-phosphate synthesis and gene and protein expression profile. Treatment of differentiated 3T3-L1 cells with 16:1n7, but not 16:0, increased basal and isoproterenol-stimulated lipolysis, mRNA levels of adipose triglyceride lipase (ATGL) and hormone sensitive lipase (HSL) and protein content of ATGL and pSer660-HSL. Such increase in lipolysis induced by 16:1n7, which can be prevented by pharmacological inhibition of PPARα, was associated with higher rates of PPARα binding to DNA. In contrast to lipolysis, both 16:1n7 and 16:0 increased fatty acid incorporation into TAG and glycerol 3-phosphate synthesis from glucose, without affecting glyceroneogenesis and glycerokinase expression. Corroborating in vitro findings, treatment of wild type, but not PPARα deficient mice with 16:1n7 increased primary adipocytes basal and stimulated lipolysis and ATGL and HSL mRNA levels. In contrast to lipolysis, however, 16:1n7 treatment increased fatty acid incorporation into TAG and glycerol 3-phosphate synthesis from glucose in both wild type and PPARα deficient mice. In conclusion, palmitoleic acid increases adipocyte lipolysis and lipases by a mechanism that requires a functional PPARα.