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.