Influence of Ageing on Glucose Homeostasis

The mechanism of age-related glucose intolerance was investigated by comparing forearm glucose uptake (FGU) during 100-g oral glucose tolerance tests (GTTs) in healthy men of different ages: group Y, 19–24 yr (n = 11); group M, 30–45 yr (n = 12); and group E, 70–83 yr (n = 9). Progressive elevation of the glucose tolerance curve occurred with increasing age, the curve of each group differing from the others at all points from 60–180 min. Although with age absolute levels of FGU were not reduced, the rise in FGU per incremental change in arterial plasma glucose concentration was significantly decreased, whereas the corresponding relationship between FGU and serum insulin was less marked. Early insulin responses were similar in all age groups, but after 60 min the curves diverged in a pattern corresponding to the respective glucose responses and differed significantly from 150–180 min. The relative changes in insulin levels corresponded to those observed in C-peptide concentrations in all groups. C-peptide ...