Deletion of prolyl carboxypeptidase attenuates the metabolic effects of diet-induced obesity

Document Type

Journal Article

Publication Date

6-15-2012

Journal

American Journal of Physiology - Endocrinology and Metabolism

Volume

302

Issue

12

DOI

10.1152/ajpendo.00544.2011

Keywords

α-melanocyte-stimulating hormone; Energy metabolism; Glucose metabolism; Insulin sensitivity

Abstract

α-Melanocyte-stimulating hormone (α-MSH) is a critical regulator of energy metabolism. Prolyl carboxypeptidase (PRCP) is an enzyme responsible for its degradation and inactivation. PRCP-null mice (PRCP gt/gt) showed elevated levels of brain α-MSH, reduced food intake, and a leaner phenotype compared with wild-type controls. In addition, they were protected against diet-induced obesity. Here, we show that PRCP gt/gt animals have improved metabolic parameters compared with wild-type controls under a standard chow diet (SD) as well as on a high-fat diet (HFD). Similarly to when they are exposed to SD, PRCP gt/gt mice exposed to HFD for 13 wk showed a leaner phenotype due to decreased fat mass, increased energy expenditure, and locomotor activity. They also showed improved insulin sensitivity and glucose tolerance compared with WT controls and a significant reduction in fasting glucose levels. These improvements occured before changes in body weight and composition were evident, suggesting that the beneficial effect of PRCP ablation is independent of the adiposity levels. In support of a reduced gluconeogenesis, liver PEPCK and G-6-Pase mRNA levels were reduced significantly in PRCP gt/gt compared with WT mice. A significant decrease in liver weight and hepatic triglycerides were also observed in PRCP gt/gt compared with WT mice. Altogether, our data suggest that PRCP is an important regulator of energy and glucose homeostasis since its deletion significantly improves metabolic parameters in mice exposed to both SD and HFD. © 2012 the American Physiological Society.

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