Carbon disulphide exposure affects the response of rat adrenal medulla to hypothermia and hypoglycaemia

The effects of hypothermia and hypoglycaemia on adrenal catecholamines and dopamine-beta-hydroxylase were compared in control and carbon disulphide (CS2) exposed rats 24 h after the last of ten daily 4 h inhalation exposures to CS2, 2 mg 1(-1) air. Animals were either kept in a cold room (0 degrees C) for 210 min with or without immobilization or were injected with insulin 100 u kg-1. Before these treatments CS2 exposed rats had more dopamine and less adrenaline in their adrenals than controls, and CS2 exposure also elevated the adrenal synthesis of catecholamines. Cold with immobilization or insulin treatment depressed the adrenal adrenaline content and increased the plasma concentrations of noradrenaline and adrenaline. There were no consistent differences between control and CS2 exposed rats. The adrenal dopamine content increased during cold exposure with immobilization or after insulin treatment both in CS2 exposed and control rats. The increase was smaller in CS2 exposed rats but the final dopamine values were nearly identical in the two groups. Exposure to cold (without immobilization) increased the adrenal dopamine content and the rate of catecholamine synthesis in control, but not in CS2 exposed rats. The increase in controls was less than the difference between the pre-cold exposure values of control and CS2 exposed rats. It is concluded that the elevation of adrenal dopamine content and catecholamine synthesis in CS2 exposed rats satisfy part of the demand placed on the adrenal medulla by hypothermia and hypoglycaemia. Consequently the changes induced by the latter treatments were smaller in CS2 exposed than in non-exposed rats. Moreover, when CS2 exposed rats were subjected to cold stress without immobilization their catecholamine synthesis was higher than the level measured in control rats after cold exposure.