The integrated effect of adrenergic blockade on glucose, fatty acid, and glycerol kinetics: responses in the basal state and during hormonal control with somatostatin-hormonal infusion.

We have used primed constant infusions of [1-13C]palmitic acid, [2-3H]glycerol, and [U-14C]glucose to evaluate the response of glucose and fat kinetics to alpha or beta adrenergic blockade in conscious dogs. The response of each blocking agent was evaluated both with and without control of the glucoregulatory hormones. When hormones were controlled, somatostatin and metyrapone were infused to block hormonal secretion, and insulin, glucagon, growth hormone, and cortisol were replaced at basal physiological rates. alpha blockade (beta stimulation) did not influence glucose production or oxidation, but it did decrease glucose clearance when hormones were controlled. Clearance did not decrease during blockade when hormones were not controlled, presumably because of the resulting increase in the plasma insulin concentration. Glucose production, plasma glucose concentration, and glucose oxidation all increased with beta blockade (alpha stimulation). alpha blockade (beta stimulation) resulted in an increase in lipolysis, whereas beta blockade (alpha stimulation) resulted in a decrease in lipolysis. In neither case, however, did FFA oxidation change. We conclude that (a) the predominant effect of unopposed stimulation is the stimulation of lipolysis, whereas unopposed alpha stimulation inhibits lipolysis. Direct effects of either alpha or beta stimulation on glucose kinetics are less dramatic, but both alpha and beta stimulation decrease glucose clearance.