Decreased norepinephrine and epinephrine contents in chromaffin tissue of rainbow trout (Oncorhynchus mykiss) exposed to diethyldithiocarbamate and amylxanthate.

1. Rainbow trout (Oncorhynchus mykiss) were exposed to 0.5 or 5.0 microM of diethyldithiocarbamate (DDC) or amylxanthate (AX) for 24 hr. 2. Both DDC (0.5-5.0 microM) and AX (5.0 microM) significantly decreased norepinephrine and epinephrine levels in the head kidney as well as the quotients epinephrine/dopamine and/or norepinephrine/dopamine. 3. The results probably reflect an inhibition of dopamine-beta-hydroxylase, the enzyme responsible for the synthesis of norepinephrine and epinephrine from dopamine. 4. It is concluded that an exposure of fish to these complexing agents could disturb physiological processes controlled by catecholamines. 5. Diethyldithiocarbamate may prove to be a valuable pharmacological tool for the study of catecholamine function in fish.