Site of action of 5-hydroxytryptophan and 5-hydroxytryptamine on the hypothalamo-pituitary-adrenal system in vitro.
5-hydroxytryptamine at a concentration of 0.04 microgram/ml was able to block the ACTH release caused by hypothalamic tissue (CRF) while it was ineffective when a hypothalamic extract containing CRF  was used. 5-hydroxytryptophan added to rat adrenal tissue caused a dose-dependent increase in corticosterone production. In a dose of 0.04 microgram/ml, 0.4 microgram/ml and 4.0 microgram/ml, 5-hydroxytryptophan was able to inhibit the ACTH release caused by hypothalamic tissue in vitro. However 0.04 microgram/ml was ineffective on the increase in ACTH secretion elicited by hypothalamic extract CRF. The data suggest that the inhibitory action of 5-hydroxytryptophan and 5-hydroxytryptamine is exerted at the hypothalamic level by inhibiting the release and/or synthesis of the corticotrophic releasing factor.
D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000311:Adrenal Glands / Q000187:drug effects*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D003345:Corticosterone / Q000378:metabolism; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism / Q000494:pharmacology; D007031:Hypothalamus / Q000187:drug effects*; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects*; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*
D012701:Serotonin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D006916:5-Hydroxytryptophan; D003345:Corticosterone