Exp Clin Endocrinol Diabetes 1999; 107(7): 431-434
DOI: 10.1055/s-0029-1212133
Article

© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

Reduction of leptin precedes fat loss from running exercise in insulin-resistant rats

M. Nara1 , T. Kanda1 , S. Tsukui1 , T. Inukai2 , T. Umeda1 , S. Inoue3 , I. Kobayashi1
  • 1Department of Laboratory Medicine, Gunma University School of Medicine, Maebashi, Japan
  • 2Dokkyo Medical School, Koshigaya, Japan
  • 3National Institute of Health and Nutrition, Tokyo, Japan
Further Information

Publication History

Publication Date:
14 July 2009 (online)

Summary

Serum concentrations of leptin, a hormone secreted into the circulation by adipocytes, correlate with body mass index. Circulating of leptin is thought to signal the brain in patients with hyperinsulinemia, a condition reported to be preventable and testable by exercise training. In the present experiments, sucrose-fed rats had reduced concentrations of leptin in portal venous blood after 4 weeks of nonforced wheel-running exercise (1.1 ± 0.1 vs. 6.2 ± 1.8 ng/mL, in nonexercised sucrose-fed rats, P < 0.05). Mesenteric and subcutaneous fat stores were similar between groups. After 12 weeks of exercise, portal vein levels of leptin concentrations (5.2 ± 2.1 vs. 9.9 ± 0.8 ng/mL, P < 0.05) and mesenteric and subcutaneous fat all were reduced in the exercise group. These results suggest that short-term running exercise reduces circulating leptin before any reduction of adipose mass, and this reduction in the concentration of leptin available to its receptors has beneficial effects on the metabolism of fat and carbohydrates.