Impaired alpha cell function in conditions with cortisol deficiency

Plasma immunoreactive glucagon (IRG), insulin (IRI) and blood glucose (BG) were evaluated in the fasting state and during an arginine test (ATT) in 6 subjects with untreated hypopituitarism (H), in 2 hypopituitary subjects with normal cortisol production (H + C), in 3 subjects with Addison's disease (A) and in 14 normal volunteers (N). No increase in BG was observed in H and A after arginine, mean values being significantly lower than in N. Mean fasting and arginine-stimulated IRI levels were lower in H and A than in N; postabsorptive arginine-induced IRG levels were significantly reduced when compared to N. In contrast IRG levels in the two H + C patients were within the normal range. The impaired IRG production in A and in H (but not in H + C) suggests a close relationship between alpha pancreatic function and cortisol levels.