Effects of Age and Sex on Postprandial Glucose Metabolism

Differences in Glucose Turnover, Insulin Secretion, Insulin Action, and Hepatic Insulin Extraction

  1. Rita Basu1,
  2. Chiara Dalla Man2,
  3. Marco Campioni2,
  4. Ananda Basu1,
  5. George Klee3,
  6. Gianna Toffolo2,
  7. Claudio Cobelli2 and
  8. Robert A. Rizza1
  1. 1Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic College of Medicine, Rochester, Minnesota
  2. 2Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, Minnesota
  3. 3Electronics and Informatics, University of Padova, Padova, Italy
  1. Address correspondence and reprint requests to Robert A. Rizza, MD, Mayo Clinic College of Medicine, 200 1st St. SW, Rm. 5-194 Joseph, Rochester, MN 55905. E-mail: rizza.robert{at}mayo.edu

Abstract

To determine the effects of age and sex on the regulation of postprandial glucose metabolism, glucose turnover, insulin secretion, insulin action, and hepatic insulin extraction were concurrently measured in 145 healthy elderly (aged 70 ± 1 years) and in 58 young (aged 28 ± 1 years) men and women before and after ingestion of a mixed meal containing [1-13C]glucose. At the time of meal ingestion, [6-3H]glucose and [6,6-2H2]glucose were infused intravenously to enable concurrent measurement of the rates of postprandial endogenous glucose production (EGP), meal appearance, and glucose disappearance. Fasting and postprandial glucose concentrations were higher (P < 0.001) in both elderly women and elderly men compared with young individuals of the same sex. The higher postprandial glucose concentrations in the elderly than young women were caused by higher rates of meal appearance (P < 0.01) and slightly lower (P < 0.05) rates of glucose disappearance immediately after eating. In contrast, higher glucose concentrations in the elderly than young men were solely due to decreased (P < 0.001) glucose disappearance. Although postprandial glucose concentrations did not differ in elderly women and elderly men, rates of meal appearance and glucose disappearance rates both were higher (P < 0.001) in the women. Fasting EGP was higher (P < 0.05) in elderly than young subjects of both sexes and in women than men regardless of age. On the other hand, postprandial suppression of EGP was rapid all groups. Insulin action and secretion were lower (P < 0.001) in the elderly than young men but did not differ in the elderly and young women. This resulted in lower (P < 0.001) meal disposition indexes in elderly than young men but no difference in elderly and young women. Total meal disposition indexes were lower (P < 0.05) in elderly men than elderly women, indicating impaired insulin secretion, whereas disposition indexes were higher (P < 0.05) in young men than young women. Hepatic insulin clearance was greater (P < 0.001) in the elderly than young subjects of both sexes but did not differ between men and women regardless of age. In contrast, the ability of glucose to facilitate its own uptake (glucose effectiveness) was higher (P < 0.001) in women than men but did not differ in elderly and young subjects. Thus, age and sex impact on insulin secretion, insulin action, hepatic insulin extraction, and glucose effectiveness, resulting in substantial differences in the regulation of postprandial glucose metabolism in men and women and in elderly and young subjects.

Footnotes

  • The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Accepted April 4, 2006.
    • Received December 30, 2005.
| Table of Contents