In a group of eighty-one fifty-five-year-old men, randomly selected from the total population, and in a group of twelve medical students, twenty-three years of age, body composition and adipose tissue fat cell size and number were determined. A 100 gm. peroral glucose tolerance test was performed, and blood glucose and plasma immunoreactive insulin were examined.
The older men showed higher glucose and particularly higher insulin responses after the glucose tolerance test than the young men. In lean older men, selected after ponderal index or body fat measurements, this was less pronounced. When a group of older men with the same fat cell diameter as the younger men was selected, the differences in glucose-insulin responses were still smaller and almost nonexisting between the two age groups. Fat cell diameter correlated only partially with ponderal index and body fat.
It was concluded that adipose tissue fat cell size is a more important determinant than adipose tissue size for the glucose and insulin res glucose tolerance test. Age has a relatively minor influence.