In oral glucose tolerance tests (GTT) performed three, four, or six hours after a previous GTT, six hours after a combined protein-glucose tolerance test or two and onehalf hours after intravenous insulin, impairment in tolerance could be closely correlated with the magnitude of the growth hormone secretory response in the previous procedure. These observations support the physiologic role of growth hormone in determining glucose tolerance.
Impairment in glucose tolerance was generally associated with an augmented integrated plasma insulin response and improvement in glucose tolerance was frequently seen in association with a lesser plasma insulin response. These observations support the view that plasma insulin follows blood glucose but that the rate of glucose disposal is determined by factors other than the level of plasma insulin alone.