Aging and insulin resistance in a group of nonobese male volunteers.

The relationship of age to insulin resistance was determined in 100 nonobese men whose ages ranged from 22 to 69 years. Seventy of the 100 subjects had normal glucose tolerance, and 30 had chemical diabetes. Insulin resistance was estimated by measuring the steady-state plasma glucose response to a continuous infusion of insulin, glucose, epinephrine, and propranolol. This approach permitted inhibition of endogenous insulin release, achievement of a comparable steady-state plasma level of exogenous insulin, and use of the height of the steady-state plasma glucose response as a direct estimate of insulin resistance. With this experimental method, no correlation was found between age and insulin resistance over the age span of the experimental population. Furthermore, there was no correlation between age and the height of the plasma glucose response to an oral glucose challenge in this population of nonobese, healthy ambulatory men.