beta-Adrenergic regulation of lipolysis and blood flow in human skeletal muscle in vivo.
Little is known about the regulation of catecholamine-stimulated lipolysis in human skeletal muscle. Therefore, beta-adrenergic regulation of lipolysis and blood flow was investigated in healthy subjects in vivo by use of microdialysis of the gastrocnemius muscle. First, during a hypoglycemic, hyperinsulinemic clamp, which induces a lipolytic response in skeletal muscle tissue, the muscle was locally perfused with beta-adrenoceptor blocking agents. Perfusion with nonselective (propranolol) and beta2-selective (ICI-118551) blocking agents counteracted the hypoglycemia-induced lipolysis (P < 0.01), but perfusion with metoprolol (beta1-blocker) did not affect the glycerol response. Second, selective beta-adrenoceptor agonists were perfused in situ into skeletal muscle during resting conditions. beta2-Adrenoceptor stimulation with terbutaline induced a concentration-dependent increase in skeletal muscle glycerol levels and in tissue blood flow, whereas perfusion with beta1- or beta3-adrenoceptor agonists (dobutamine or CGP-12177) did not influence the glycerol concentration or blood flow. In conclusion, in skeletal muscle tissue, only the beta2-subtype is of importance among beta-adrenoceptors for regulation of lipolysis and blood flow. This is in contrast to adipose tissue, where beta1- and beta3-adrenoceptors are also involved.
Hagström-Toft
E
E
Department of Medicine and Research Center, Huddinge Hospital, Karolinska Institute, S-141 86 Huddinge, Sweden.
Enoksson
S
S
Moberg
E
E
Bolinder
J
J
Arner
P
P
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000328:Adult; D005260:Female; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D006946:Hyperinsulinism / Q000378:metabolism / Q000503:physiopathology; D007003:Hypoglycemia / Q000378:metabolism / Q000503:physiopathology; D008066:Lipolysis / Q000187:drug effects / Q000502:physiology*; D008297:Male; D017551:Microdialysis; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology
D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; D005990:Glycerol