Alpha-adrenergic control of growth hormone release during surgical stress in man

The mechanisms involved in the initial release of growth hormone (GH) during cholecystectomy have been studied after the administration of phentolamine in saline and in isotonic glucose, and after the administration of 10% glucose. Infusion of these substances was started 10 min before and terminated 30 min after skin incision. The serum GH levels 30 min after skin incision in a nontreated control group were raised to 14.4 ± 1.0 ng/ml. The alpha-adrenergic blockade by phentolamine (20 mg during 40 min) regardless of whether administered in saline or in isotonic glucose inhibited GH response to surgery (4.3 ± 2.1 ng/ml, or 2.2 ± 0.4 ng/ml). The administration of 10% glucose (40 g during 40 min) led to a diminished response in some, but not in all the patients (6.2 ± 1.2 ng/ml). It is concluded that the alpha-adrenergic mechanism participates in GH response to surgery.