Localization of Catecholamines in Brown Fat

Abstract

THE role of interscapular brown fat in non-shivering heat production is well established in new-born rabbits¹, new-born guinea-pigs², and during arousal from hibernation³. Heat is produced by the local oxidation of long-chain fatty acids. Regulation of heat production by the autonomic nervous system is strongly suggested by the fact that intravenous infusion of noradrenaline in physiological amounts stimulates heat production, and this heat production is abolished by pronethalol¹. Stimulation of the cervical sympathetic chain in new-born rabbits causes a local increase in brown fat temperature above the deep-body temperature⁴. Fat cells contain a lipase which can be activated by catecholamines⁵. Brown fat from the interscapular region of adult rats contains a large amount of noradrenaline, which disappears rapidly after denervation or treatment with reserpine⁶. Brown fat is also richly innervated with non-medullated autonomic nerve fibres terminating in relation to fat cells⁷.