Potentiation of the L-5-hydroxytryptophan-induced elevation of plasma corticosterone levels in rats by a specific inhibitor of serotonin uptake.

The ability of L-5-hydroxytryptophan (L-5HTP), a serotonin precursor, to elevate plasma levels of corticosterone in rats was confirmed. Pretreatment of the rats with 3-(p-trifluoromethylphenoxy)-N-methyl-3-phenyl-propylamine hydrochloride (Lilly 110140) markedly enhanced the elevation of corticosterone levels by L-5HTP. Since Lilly 110140 is a specific inhibitor of serotonin uptake, these results support the hypothesis that L-5HTP elevates corticosterone by enhancing neurotransmission through a serotoninergic pathway influencing ACTH release.