Effect of insulin on human adipose tissue metabolism in situ. Interactions with beta-adrenoceptors

Abstract
The effects of insulin, and its interactions with catecholamines through beta-adrenoceptors, on human adipose tissue glucose utilization and lipolysis were investigated in vivo. Microdialysis of the extracellular compartment of abdominal subcutaneous adipose tissue was performed in healthy subjects of normal weight, before and during a 2-h hyperinsulinaemic (61±3 mU/l), euglycaemic clamp. The tissue was perfused with or without the beta-adrenergic agonist isoproterenol (10mol/l), and the tissue dialysate concentrations of glucose, glycerol (lipolysis index) lactate and pyruvate were determined. During the insulin infusion, glucose in adipose tissue decreased by 20% (ppp<0.05–0.005).Itis concluded that insulin action on glucose uptake and lipolysis in human adipose tissue in vivo is counteracted by beta-adrenoceptor stimulation. In contrast, insulin and beta-adrenoceptors have synergistic effects on non-oxidative glucose metabolism in human adipose tissue in situ.