Hyperinsulinemia of obesity is due to decreased clearance of insulin

Am J Physiol. 1983 Aug;245(2):E155-9. doi: 10.1152/ajpendo.1983.245.2.E155.

Abstract

The hyperinsulinemia of obesity could result from a decrease in the metabolic clearance rate of insulin (MCR-I), an increase in the secretory rate of insulin (SR-I), or a combination of both these processes. Because C-peptide and insulin are secreted in an equimolar ratio, the plasma concentrations of C-peptide (C) and insulin (I) are inversely proportional to their rates of metabolic clearance (C/I = MCR-I/MCR-C). We obtained 24-h integrated concentrations (IC) of insulin (IC-I) and C-peptide (IC-C) in 23 obese and 45 nonobese subjects over a period of normal activity and food intake. The IC-I was 69% higher in the obese subjects (P less than 0.0001). A 13% increase in the IC-C (P = 0.04), with a constant rate of C-peptide clearance, indicates a proportionate increase in SR-I. A 33% decrease in the IC-C/IC-I in the obese group (P less than 0.005) reflects a decrease in MCR-I; hence, 75% of the hyperinsulinemia is due to a decrease in the clearance of insulin. Because peripheral MCR-I (pMCR-I) is similar in obese and nonobese subjects, the decrease in MCR-I may be due to a decrease in the hepatic clearance of insulin. This conclusion was supported by our comparison of 24-h IC-C/IC-I ratios in the obese and nonobese subjects. Whereas the 24-h IC-C/IC-I of the nonobese resembled the fasting state, the 24-h IC-C/IC-I of the obese resembled the postprandial state, when insulin removal by the liver is known to be suppressed. These data are consistent with a decreased 24-h hepatic MCR-I (hMCR-I) as the cause of the hyperinsulinemia of obesity.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Blood Glucose / analysis
  • Body Height
  • Body Weight
  • C-Peptide / metabolism
  • Fasting
  • Female
  • Humans
  • Hyperinsulinism / etiology*
  • Hyperinsulinism / metabolism
  • Insulin / metabolism*
  • Male
  • Metabolic Clearance Rate
  • Middle Aged
  • Obesity / complications*
  • Obesity / metabolism

Substances

  • Blood Glucose
  • C-Peptide
  • Insulin