The release of adrenaline and noradrenaline from the adrenal medulla of the cat during splanchnic stimulation.

Cats were anaesthetized with chloralose, eviscerated and the right adrenal gland was removed. The venous outflow from the left adrenal gland was collected during 10 five-minute periods of stimulation of the left splanchnic nerve. The amounts of adrenaline and noradrenaline in the venous outflow and in the stimulated and unstimulated glands were determined by a fluorimetric method. In eight experiments a mean of 50.5 mug. of total catechol amine was recovered from the effluent blood. The mean difference in amine content between the stimulated and unstimulated glands was 50 mug., representing a loss of 29% from the stimulated gland. The proportions of the two amines in the effluent blood were very similar to those found in the gland. The results provide no evidence for an increase in the rate of synthesis of catechol amines during splanchnic stimulation.