High and low insulin responders: relations to oral glucose tolerance, insulin secretion and physical fitness.

Abstract

High and low insulin responders, a total of 133 non-diabetic men, matched for age and body weight, were reinvestigated after an average period of 3 1/2 years by means of oral glucose tolerance tests, simultaneous insulin and C-peptide measurements and submaximal work tests. The number of individuals with impaired glucose tolerance did not increase during the observation period, and none became diabetic. Intergroup differences in glucose and insulin values were largely the same as in the initial screening procedure, although some regression towards the mean was observed. The high insulin group, compared with the low insulin group, had overall higher glucose, insulin and C-peptide levels, significantly higher increment 0-40 min of insulin but not C-peptide, and significantly lower maximal oxygen uptake. The present data indicate no difference in insulin secretory capacity but a decreased hepatic insulin extraction and a peripheral insulin insensitivity among the high insulin responders, related to a lower degree of physical fitness.