Effects of autonomic blocking agents on growth hormone, insulin, free fatty acids and glucose in baboons.

Abstract

The effects of autonomic blocking agents on serum GH, immunoreactive insulin (IRI), plasma FFA and plasma glucose were studied in fasted conscious baboons adapted to living in primate chairs. Alpha adrenergic blockade with phentolamine significantly depressed GH secretion and resulted in an increase in IRI and a fall in glucose. Beta adrenergic blockade with propranolol or butoxamine and ganglionic blockade with trimethaphan (Arfonad) were associated with a significant prompt rise in GH, and decreases in IRI, FFA and plasma glucose. When beta adrenergic or ganglionic blockade was superimposed upon alpha adrenergic blockade, the GH-elevating effects of beta and ganglionic blockade were prevented, suggesting direct effects of these agents upon GH secretion independent of hemodynamic changes and hypoglycemia. These data show that blockade of adrenergic mechanisms causes synchronous reciprocal changes in GH and IRI and suggest that alpha adrenergic activity stimulates, and beta adrenergic activity inhibits, the release of GH. (Endocrinology86: 77, 1970)