Endurance training increases leptin expression in the retroperitoneal adipose tissue of rats fed with a high-sugar diet.
Lipids 2013;
49:85-96. [PMID:
24243000 PMCID:
PMC3889676 DOI:
10.1007/s11745-013-3854-7]
[Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 10/10/2013] [Indexed: 12/16/2022]
Abstract
The presence of leptin receptors in white adipose tissue (WAT) suggests a type of peripheral control during the development of obesity and other metabolic disorders. Both diet composition and exercise influence serum leptin; however, the effect of their combination on long-term WAT leptin metabolism is unknown. In this study, rats fed with standard or high-sugar diets (HSD) were simultaneously subjected to running training for 4- and 8-week periods, and the retroperitoneal WAT (rWAT) was evaluated for adipocyte cell size, lipid and catecholamine content, Lep, OB-Rb and Ucp2 mRNA transcription levels, and circulating leptin and non-esterified fatty acids (NEFA). The HSD groups displayed a higher adiposity index and rWAT weight, Lep mRNA and protein upregulation, and a period-dependent effect on OB-Rb mRNA expression. Exercise decreased serum leptin and upregulated the OB-Rb mRNA levels. However, in rats fed with an HSD, the increase in OB-Rb mRNA and reduction in catecholamine levels resulted in a high level of adiposity and hyperleptinemia. The combination of training and an HSD decreases the NEFA levels and upregulating the Ucp2 mRNA expression in the 4-week period, while downregulating the Ucp2 mRNA expression in the 8-week period without changing the NEFA levels. Our results suggest that an HSD induces an increase in leptin expression in rWAT, while reducing adipocytes via leptin-mediated lipolysis after an 8-week period. In exercised rats fed an HSD, TAG synthesis and storage overlaps with lipolysis, promoting fat store development and Lep mRNA and plasma protein upregulation in adult rats.
Collapse