A 38-year-old man had an acute onset of consciousness loss, pyrexia and hyponatremia. Plasma Adrenocorticotropic Hormone (ACTH)and cortisol levels were low. Plasma ACTHfailed to respond to corticotropin-releasing hormone (CRH)and insulin-induced hypoglycemia whereas i.m. injection of ACTH-Zraised plasma cortisol. Plasma insulin-like growth factor-I (IGF-I) and urine growth hormone (GH) concentrations were also low and plasma thyroid-stimulating hormone(TSH) level was rather elevated. Plasma IGF-I and TSHlevels were not completely normalized by glucocorticoid (GC) replacement alone although plasma GHresponses to pharmacological stimuli were normalized. The GCreplacement in combination with daily s.c. injection of recombinant human GH(rhGH) not only normalized plasma IGF-I and IGFBP-3 levels, but also further lowered the plasma TSHlevel, possibly due to an increased T4/T3 conversion, which resulted in a beneficial change in body composition. (Internal Medicine 34: 688-691, 1995)