VASCULAR AND LIPOLYTIC RESPONSES OF THE INGUINAL FAT PAD OF THE SHEEP TO ADRENERGIC STIMULATION, AND THE EFFECTS OF DENERVATION AND AUTOTRANSPLANTATION

¹ A.F.R.C. Institute of Animal Physiology, Babraham, Cambridge CB2 4AT

Electrical stimulation of sympathetic nerves supplying an inguinal fat pad, in the anaesthetized sheep, produced effects on blood flow through the fat pad which differed when the nerves were intact or sectioned. Lipolysis was stimulated and the output of individual fatty acids into venous plasma was compared with their composition in the adipose tissue triglycerides. Close-arterial infusion of noradrenaline also produced lipolysis but, again, effects on the circulation differed when the fat pad was in situ or chronically autotransplanted to the neck. Close-arterial infusion of dopamine produced a similar response to noradrenaline. It is concluded that sympathetic nerves and noradrenaline may have a predominantly vasodilatory effect on adipose tissue in the sheep, but the response after acute or chronic denervation is predominantly vasoconstriction. Noradrenaline and dopamine stimulate fat mobilization independently, but the fatty acids mobilized may not be entirely representative of those stored in the adipose tissue triglyceride.