Evidence for the role of adrenocortical hormones in the regulation of noradrenaline and dopamine metabolism in certain brain areas.

1 Bilateral adrenalectomy suppressed body growth and increased the activity of tyrosine hydroxylase in rat striatum in a time-dependent manner. Fifteen days after adrenalectomy, the concentrations of noradrenaline were decreased significantly in hypothalamus and striatum, as were those of dopamine in brain stem and striatum. 2 Catechol-O-methyltransferase failed to change in response to adrenalectomy, but the activity of monoamine oxidase in cortex was significantly increased 7 days after surgery. These changes in various neurochemical parameters were even more pronounced 15 days after adrenal ablation. 3 Administration of corticosterone (10 mg/kg i.p.) to adrenalectomized rats effectively reversed the observed effects on brain amine metabolism. Corticosterone treatment for 7 days beginning from the 8th day of adrenalectomy virtually restored the concentrations of noradrenaline and dopamine as well as the activities of striatal tyrosine hydroxylase and cerebrocortical monoamine oxidase to the values seen for sham-operated controls. 4 Our data suggest that changes seen in brain noradrenaline and dopamine of adrenalectomized rats are specific to adrenocortical steroids and that these hormones play a role in the regulation of catecholamine formation.