DIFFERENTIAL-EFFECTS OF INSULIN-INDUCED AND PROINSULIN-INDUCED HYPOGLYCEMIA ON PITUITARY-HORMONE AND CATECHOLAMINE SECRETION

Abstract

The effects of insulin- and proinsulin-induced hypoglycemia on pituitary hormone and catecholamine secretion were compared in normal men to search for possible hypothalamic or pituitary inhibitory effects of proinsulin on glucocounterregulatory responses. When subjects received 0.1 U/kg i.v. human insulin and 25-38 micrograms/kg i.v. human proinsulin on separate occasions, plasma glucose decreased more rapidly after insulin, and the nadir was slightly lower, but integrated hypoglycemic responses were similar. Cortisol, growth hormone (GH), prolactin, epinephrine, and norepinephrine responses occurred more rapidly after insulin than after proinsulin. Peak and integrated cortisol, GH, and cate..