In vivo inhibition of dopamine-beta-hydroxylase in rat adrenals during exposure to carbon disulphide.

Male rats were exposed for a maximum of 4 h to carbon disulphide at atmospheric levels of 1.0-4.0 mg/l and the turnover rates of adrenal dopamine was determined by injecting alpha-methyl-p-tyrosine and measuring the rate at which dopamine disappears. Although the level of exposure was significantly higher than the 30.0 micrograms/l permissible limit, or the average occupational exposure, similar or even higher peak exposure values were reported from the viscose rayon industry. After inhibition of tyrosine hydroxylase by alpha-methyl-p-tyrosine, adrenal dopamine contents declined at a slower rate in rats exposed to carbon disulphide than in controls. The reduced rate of dopamine metabolism during exposure to carbon disulphide indicates inhibition of dopamine-beta-hydroxylase in vivo. The size of this effect, which could be detected as soon as 30 min after starting the exposure to carbon disulphide, was dose dependent. The rate of dopamine turnover was still reduced 2 h after the end of a single exposure. However at that time, because of the larger dopamine pool present in the adrenals, the amount of dopamine converted per unit of time was again at pre-exposure levels.