Accumulation of intra-arterially administered [3H]adrenaline and [3H]noradrenaline in various tissues of the Atlantic cod, Gadus morhua

The accumulation of intra-arterially administered radiolabelled adrenaline and noradrenaline was studied in various tissues of the Atlantic cod, Gadus morhua. The largest uptake was seen in the posterior cardinal vein (chromaffin tissue), head kidney, kidney, heart and gill filaments. All these tissues, except the heart, also accumulated noradrenaline to a greater extent than adrenaline. The heart, spleen, gas gland and muscularis mucosae of the swimbladder instead favoured adrenaline accumulation. Small amounts of the injected label (both adrenaline and noradrenaline) were also recovered in the intestine, liver and hypothalamus. The lowest detectable amine accumulation was seen in the rest of the brain and in the skeletal muscle. It is suggested that innervation density, blood flow to the tissue and the concentration of circulating and endogenously stored amine, as well as the affinity of the amine for the degrading enzymes and a possible stereospecificity of the uptake mechanisms, determine the rate and preference of accumulation between the amines.