CYCLLE 3′-5′-ADENOSINE MONOPHOSPHATE IN HYPOPITUITARISM AND SILVER-RUSSEL SYNDROME

Abstract

The urinary excretion of cyclic 3'-5'-adenosine monophosphate (c-AMP) was studied in 5 patients with idiopathic hypopituitarism during two -day periods before and during administration of 5 mg of human growth hormone (HGH) per day. In 4 out of these 5 patients the urinary excretion of c-AMP was normal and not modified by the administration of HGH. In one patient, however, urinary c-AMP was found to be absent during 2 consecutive days following an insulin tolerance test performed in the control period. The effect of dibutyryl c-AMP (0.2 mg/kg.min during 60 min) on plasma glucose, immunoreactive insulin (IRI), growth hormone (GH) and cortisol was investigated in 8 patients with idiopathic hypopituitarism and in 2 patients with the Silver-Russell syndrome. Plasma glucose and IRI increased markedly in all patients. An increased level of cortisol was also observed except in 1 hypopituitary patient presumably having ACTH deficiency. Although the 2 Silver-Russell patients showed a net increase of plasma GH at 120 min., 7 out of the 8 hypopituitary patients failed to increase the level of plasma GH above 1 ng/ml. In 1 patient, however, the cyclic nucleotide provoked an increase of plasma GH up to 5 ng/ml. The significance of these findings for the investigation of GH-deflciency is discussed.