Tryptophan metabolism oral contraceptives

Modern low-dose estrogen oral contraceptives do not affect tryptophan metabolism, although they may cause increased plasma and erythrocyte concentrations ofpyridoxal (Masse et al., 1996). 

Adams PW, Wynn V, Folkard J, and Seed M (1976) Influence of oral contraceptives, pyri-doxine (vitamin Be) and tryptophan on carbohydrate metabolism. Lancet (1), 759-64. 

Some women suffer from mental deprc.ssion when taking estrogen-containing oral contraceptives, and this depression could be due to another malfunction in tryptophan metabolism, leading to S-hydroxytryptamine (serotonin). Some evidence indicates that the decarboxylation of S-hydroxytrypto-phan is inhibited (in vitro) by estfogen conjugates competing with pyridoxal phosphate for the decarboxylase apoenzyme. 

Many attempts have been made to determine whether medications were influential as a risk factor. Although use of a prescription or nonprescription medication did not differ substantially between case patients and controls, it appeared that the use of an antidepressant or psychotropic medication (any antipsychotic, antidepressant, benzodiazepines, and/or other anxiolytic) could increase the risk of developing EMS.22-67 It is of interest that a number of medications, such as corticosteroids, oral contraceptives, and estrogen, which can alter tryptophan metabolism, have not been determined to have an effect on the development of EMS. Actually, some clinicians have postulated that EMS itself may be caused by or related to abnormal tryptophan metabolism.42 68... 

Depression has been described in women taking oral contraceptives (Al, Bl, H9, L6, W8) although a causal relationship has not been convincingly demonstrated (L3, W5). There has been interest lately in depression in OCA-users because these women often manifest abnormalities in tryptophan metabolism and because depressive illnesses may be associated with abnormal brain neuroamine metabolism. 

Brin, M., Abnormal tryptophan metabolism in pregnancy and with the oral contraceptive pill. I. Specific effects of an oral estrogenic contraceptive steroid on the tryptophan oxygenase and two aminotransferase activities in livers of ovariectomized-adrenalectomized rats. Amer. J. Clin. Nutr. 24, 699-703... 

R9. Rose, D, P., and Adams, P. W., Oral contraceptives and tryptophan metabolism. Effects of oestrogen in low dose combined with a progestagen and of a low-dose progestagen (megestrol acetate) given alone. J. Clin. Pathol. 25, 252-258 (1972). 

R16. Rose, D. P., Strong, R., Adams, P. W., and Harding, P. E., Experimental vitamin Ba deficiency and the effect of oestrogen-containing oral contraceptives on tryptophan metabolism and vitamin Ba requirements. Clin. Sci. 42, 465-477 (1972). 

Rose [305] reported the excretion of grossly increased amounts of xanthurenic acid in the urine of women taking combination products. A similar increase in tryptophan metabolites occurs in pregnancy and has been interpreted as indicating pyridoxine deficiency [306]. Dewhurst [307] subsequently postulated a causal connection between dysfunction of trytophan metabolism and certain types of depression. Winston [308] developed the concept further by suggesting that depression from oral contraceptive medication be treated with pyridoxine. Price and Toseland [309] have proposed routine inclusion of pyridoxine in oral contraceptive preparations. Developments will be awaited with interest. 

Vitamin B-6 and oral contraceptive agents—Recent studies indicate that the vitamin B-6 requirement for most oral contraceptive users is approximately the same as that for nonusers thus, the current evidence does not appear to justify the routine supplementation of the dietary vitamin B-6 with pyri-doxine. However, some women report that depression occurs when they are taking oral contraceptives, probably as a result of the failure to convert tryptophan to serotonin, a neurotransmitter in the brain. When this problem occurs, the physician may suggest higher levels of vitamin B-6 (about 30 mg daily) in order to normaiize tryptophan metabolism. 

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