Adrenocorticoids control 5-hydroxytryptamine metabolism in rat brain.
The influence of surgical adrenalectomy was examined on the biosynthetic capacity for 5-hydroxytryptamine of rat brain. The results demonstrate that adrenalectomy decreased tryptophan hydroxylase activity and its substrate tryptophan in the brain stem. A parallel change in the concentration of 5-hydroxytryptamine was seen in brain stem and striatal region of adrenalectomized rats. In contrast, the level of 5-hydroxyindoleacetic acid was significantly elevated in both of these brain regions. Replacement therapy with corticosterone (10 mg/kg i.p.) produced time-dependent increases in tryptophan, tryptophan hydroxylase and 5-hydroxytryptamine and decreases in 5-hydroxyindoleacetic acid levels. Alterations in these neurochemical parameters were more conspicuous in adrenalectomized rats receiving corticosterone for 7 days as compared to those given only for 3 days. Our data demonstrate that adrenocortical hormones regulate brain 5-hydroxytryptamine synthesis probably by enhancing both the levels of tryptophan and the activity of rate-limiting enzyme tryptophan hydroxylase. It is postulated that emotional instability seen during altered adrenocortical function might partly be associated with abnormal metabolism of central 5-hydroxytryptamine.
D000305:Adrenal Cortex Hormones / Q000502:physiology*; D000315:Adrenalectomy; D000818:Animals; D001921:Brain / Q000378:metabolism*; D001933:Brain Stem / Q000378:metabolism; D003345:Corticosterone / Q000494:pharmacology; D008297:Male; D051381:Rats; D012701:Serotonin / Q000096:biosynthesis*; D014364:Tryptophan / Q000378:metabolism; D014365:Tryptophan Hydroxylase / Q000378:metabolism
D000305:Adrenal Cortex Hormones; D012701:Serotonin; D014364:Tryptophan; D014365:Tryptophan Hydroxylase; D003345:Corticosterone