We prospectively evaluate pituitary functions in patients in the acute phase after TBI or SAH and a control group of patients with trauma not involving the brain. Endocrine data included basal anterior pituitary lobe hormone, IGF-1 and testosterone serum levels (Immulite 2000) within the first 8 hours after TBI or SAH. Further endocrine evaluation was performed by means of either a combined GHRH-arginine-CRH-LHRH test or an insulin-induced hypoglycemia test after 4 months and 12 months. To rule out an assay related bias with regard to GH and IGF-1, all hormone levels were cross-checked by a supersensitive assay in another laboratory.