Impairment of noninsulin-mediated glucose disposal in the elderly

Graydon S. Meneilly, Dariush Elahi, Kenneth L. Minaker, Anne L. Sclater, John W. Rowe

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

While normal aging is characterized by resistance to insulin-mediated glucose disposal (IMGU), the effect of age on noninsulin-mediated glucose disposal (NIMGU), which is responsible for the majority of basal glucose uptake, has not been completely evaluated. These studies were conducted on healthy nonobese young (n = 10; age, 20–30 yr) and old (n = 10; age, 62-80 yr) men. Each subject underwent two paired studies in random order. In all studies a [3H]glucose infusion was used to measure glucose uptake and production rates, and somatostatin (500 μg/h) was infused to suppress endogenous insulin release. In study A, plasma glucose was kept close to fasting levels (5.6 mmol/L) using an euglycemic clamp protocol for 4 h. Plasma insulin decreased to less than 20 pmol/L within 15 min and remained suppressed thereafter in all studies. Steady state (15–240 min) plasma glucagon levels were slightly greater in the elderly [young, 86 ± 5 (±se); old, 98 ± 2 ng/L; P < .05]. Basal glucose uptake was similar in both groups (young, 877 ± 21; old, 901 ± 24 μmol/min). Glucose uptake during the last hour of the study (180–240 min) was used to represent NIMGU, because insulin action was assumed to be absent by this time. NIMGU was less in the elderly (young, 744 ± 18; old, 632 ± 32 μmol/min; P < 0.01). In study B, plasma glucose was kept at about 11 mmol/L for 4 h using a hyperglycemic clamp protocol. Plasma insulin decreased to less than 20 pmol/L within 15 min and remained suppressed thereafter in all studies. Steady state plasma glucagon levels were slightly but not significantly higher in the elderly (young, 88 ± 6; old, 100 ± 4 ng/L). Basal glucose uptake (young, 910 ± 27; old, 883 ± 25 μmol/min) and NIMGU (young, 933 ± 36; old, 890 ± 16 μmol/min; P = NS) were similar in both young and old subjects. We conclude that aging is associated with impairment in NIMGU only in the basal state, which may explain in part the increase in fasting glucose with age.

Original languageEnglish
Pages (from-to)566-571
Number of pages6
JournalJournal of Clinical Endocrinology and Metabolism
Volume68
Issue number3
DOIs
StatePublished - Mar 1989
Externally publishedYes

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