Intraperitoneal administration of 2-cyclooctyl-2-hydroxyethylamine (CONH; 25–75 mg/kg) produced dose-related reductions in the epinephrine (EPI) concentrations in both the hypothalamic and brainstem regions, but not in the adrenal glands. The reductions in the hypothalamic and brainstem EPI concentrations in rats anesthetized with pentobarbital sodium were accompanied by parallel increases in blood glucose. These data suggest that CONH induces its hyperglycemia action at least in part by altering central EPI biosynthesis. This hyperglycemic was antagonized by spinal transection or adrenalectomy, but not by vagotomy. This indicates that CONH increases the adrenal-sympathetic efferent activity and leads to hyperglycemia in rat