The Arginine Provocative Test: An Aid in the Diagnosis of Hyposomatotropism

Abstract

Comparisons have been made of the secretion of growth hormone (HGH) following the induction of hypoglycemia with insulin and that induced by arginine infusion (0.5 g/kg /30 min) in order to determine the reliability of the latter procedure in the diagnosis of disturbances in growth hormone secretion in children and adult patients. In 49 normal individuals tested with arginine, the HGH level rose to a peak concentration of 21 mμg/ml; in 105 normal individuals tested with hypoglycemia, the mean peak concentration was 17 mμg/ml. The mean peak concentration in plasma HGH in both tests was slightly, but not significantly, higher in women than men. The growth hormone rise in response to arginine was not dependent on prior insulin secretion, for a normal rise was observed in 12 juvenile diabetic patients tested. In 17 normal individuals who were pair-tested, the coefficient correlation between the peak HGH level attained following arginine and following hypoglycemia was 0.20; in 23 children with growth retardation who were pair-tested the coefficient of correlation was 0.58. Of the 12 patients suspected of having pituitary dwarfism by clinical criteria, 8 failed to respond to arginine, 9 failed to respond to hypoglycemia. Of the 11 patients suspected of having constitutional delay by clinical criteria, 1 failed to respond to arginine, 5 failed to respond to hypoglycemia. The arginine infusion is an innocuous, reliable stimulus of growth hormone secretion in the study of patients in the diagnosis of hyposomatotropism, which avoids the undesirable side-effects of insulin- induced hypoglycemia.