Horm Metab Res 2009; 41(1): 46-49
DOI: 10.1055/s-0028-1087207
Animals, Clinical

© Georg Thieme Verlag KG Stuttgart · New York

The Effect of Chronic Hyperinsulinemia on Plasma Adiponectin Levels in Sprague-Dawley Rats

Y. Kamari 1 , E. Peleg 1 , M.-O. Herman 1 , M. Bursztyn 2 , E. Grossman 1 , Y. Sharabi 1 , 3
  • 1Hypertension Unit and Internal Medicine D, The Chaim Sheba Medical Center, Tel Hashomer, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
  • 2Hypertension Unit, Hadassah University Hospital, Mount Scopus, Jerusalem, Israel
  • 3Clinical Neurocardiology, National Institute of Health, Bethesda, Maryland, USA
Further Information

Publication History

received 14.04.2008

accepted 07.07.2008

Publication Date:
23 October 2008 (online)

Abstract

Adiponectin is an important vascular protective substance whose levels are reduced in states of insulin resistance. The relationships between plasma insulin levels and adiponectin are not fully understood, and it is not known whether it is the elevated circulating levels of insulin or insulin resistance that directly affects adiponectin levels. The present study evaluates the direct effect of chronic hyperinsulinemia on plasma adiponectin levels. Male Sprague–Dawley rats were treated with insulin (n=15) administered by a sustained-release implant or were given a sham implantation (n=10) as a control group. Body weight, systolic blood pressure, plasma glucose, triglycerides, insulin, and adiponectin were measured at baseline and after 20 and 40 d of treatment. Insulin-treated rats and controls showed a similar increase in body weight. The insulin-treated group had a significant increase in plasma insulin levels and a decrease in plasma glucose levels compared with the sham group, with no change in blood pressure or triglyceride levels. Adiponectin levels remained unchanged despite the significant increase in insulin levels. High circulating insulin levels do not affect plasma adiponectin levels. These results support the concept that the primary defect that results in insulin resistance and hyperinsulinemia is responsible for the altered plasma adiponectin levels in the metabolic syndrome and type 2 diabetes.

References

Correspondence

Dr. Y. Kamari

Hypertension Unit, Internal Medicine D

C. Sheba Medical Center

52621 Tel Hashomer

Israel

Phone: +972/3/530 26 24

Fax: +972/3/535 54 28

Email: [email protected]