Correlative studies of growth hormone and insulin plasma concentrations with metabolic abnormalities in acromegaly.

As a consequence of chronic hypersecretion of growth hormone, the acromegalic patients manifested impaired glucose tolerance, despite a mean plasma insulin response which was 3 times normal.

Abstract

Abstract Growth hormone concentrations were measured in the plasma of 59 individuals with acromegaly. In addition, 12 acromegalic patients were studied during oral glucose, intravenous insulin, and intravenous tolbutamide tolerance tests for changes in blood glucose and plasma insulin, nonesterified fatty acids (NEFA), and growth hormone concentrations. The acromegalic subjects had higher than normal plasma growth hormone concentrations which did not change following hypoglycemia or hyperglycemia to the same degree as those of the control subjects. As a consequence of chronic hypersecretion of growth hormone, the acromegalic patients manifested impaired glucose tolerance, despite a mean plasma insulin response which was 3 times normal. This antagonism to insulin cannot be attributed to alterations in fasting plasma NEFA levels.