Serotonin metabolism and depression in oral contraceptive users.

Serotonin and nicotinic acid ribonucleotide metabolic pathways of tryptophan metabolism were studied before and after tryptophan load test in thirty women using oral contraceptive steroids for a period of 2 to 5 years. Ten of them were suffering from depression. Another ten healthy women participated in this study as a control group. Twenty-four-hour urinary excretion of serotonin, 5-hydroxyindole acetic acid and total 5-hydroxyindoles were estimated as indices of serotonin pathway metabolites, while xanthrenate excretion was determined as an index of tryptophan oxygenase pathway. Plasma cortisol, urinary 17-oxosteroids and 17-hydroxycorticosteroids were determined to assess adrenal cortical function. Urinary creatinine output was assayed to check the adequacy of 24-hr urine collection. The changes induced by oral contraceptive steroids on tryptophan and corticosteroid metabolism were correlated with the associated depression. Changes in serotonin metabolism were demonstrated in the depression group before and after tryptophan load test, while in the non-depression group before and after tryptophan load test, while in the non-depression group, these changes were only demonstrated after tryptophan load test. Results indicated the alteration in tryptophan metabolism are usually well compensated in the non-depression group but may accentuate or precipitate the development of depression in susceptible women.