Effect of Hypophysectomy on Monoamine-synthesizing Enzyme Activities in Rat Brain and Adrenal Gland / 대한정신약물학회지

ABSTRACT

In an attempt to investigate the regional specificity of effect of pituitary hormones on the activities of tyrosine hydroxylase(TH) and tryptophan hydroxylase(TPH), which are the rate-limiting enzymes in catecholamine and serotonin biosyntheses, respectively, the authors measured enzyme activities after hormonal deprivation, using the hypophysectomized animal model. The results are summarized as follows. First, whereas body weights of sham-operated group were increased gradually over time, those of hypophysectomized group were little changed. Second, the change of TH activity between sham-operated and hypophysectomized groups was not observed in each region of brain. Third, the change of TPH activity between two groups also was not observed in dorsal raphe nucleus and hypothalamus. It appears from the above findings that neural stimuli may be much more significant in the maintenance of normal level of TH and TPH in the brain than hormonal stimuli, and endocrine hormones might not directly affect monoaminergic neurotransmission in the absence of stress.