Bilateral adrenalectomy does not alter stress-induced increases in noradrenaline turnover in rat brain regions.

Effects of adrenalectomy on increases in noradrenaline (NA) turnover induced by a one-hour immobilization stress were examined by measuring the levels of NA and its major metabolite, 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4) in specific brain regions of the rat. Bilateral adrenalectomy alone does not affect basal levels of NA and MHPG-SO4 in the brain regions examined with the exception of an increase in MHPG-SO4 levels in the hypothalamus and a decrease in NA levels in the cerebral cortex. In sham-operated rats, immobilization stress caused significant increases in MHPG-SO4 levels in five brain regions that were examined, i, e., the hypothalamus, amygdala, hippocampus, cerebral cortex and pons plus medulla oblongata, and significant decreases in NA levels in the hypothalamus and amygdala. These changes in NA and MHPG-SO4 levels induced by stress were not affected by bilateral adrenalectomy. These results suggest that corticosterone is not a causative factor in enhancing brain NA turnover during immobilization stress.