Neuroendocrine Responses to Tryptophan as an Index of Brain Serotonin Function

  • P. J. Cowen
Part of the NATO ASI Series book series (volume 20)


Drugs that increase brain serotonin (5-hydroxytryptamine, 5-HT) function elevate plasma levels of certain anterior pituitary hormones, notably prolactin (PRL), ACTH and growth hormone (GH) (1). Administration to humans of the serotonin precursor L-tryptophan (LTP), reliably elevates plasma PRL concentration (1). The present chapter reviews the evidence that this neuroendocrine response is mediated by increases in brain 5-HT function and also examines whether abnormal PRL responses to LTP are seen in depressed patients.


Depressed Patient Growth Hormone Response Neuroendocrine Response Anterior Pituitary Hormone Prolactin Response 
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  1. 1).
    COWEN, P. J., ANDERSON, I. M. (1986). 5-HT Neuroendocrinology. In: The Biology of Depression. ( Deakin, J. F. W., ed.). Royal College of Psychiatrists special publication, pp. 71–89.Google Scholar
  2. 2).
    CHECKLEY, S. A. (1980). Neuroendocrine tests of monoamine function in man: a review of basic theory and its application to the study of depressive illness. Psychol. Med. 10: 35–53.PubMedCrossRefGoogle Scholar
  3. 3).
    COWEN, P. J., GADHVI, H., GOSDEN, B., KOLAKOWSKA, T. (1985). Responses of prolactin and growth hormone to L-tryptophan infusion: effects in normal subjects and schizophrenic patients receiving neuroleptics. Psychopharmacology 86: 164–169.PubMedCrossRefGoogle Scholar
  4. 4).
    NUTT, D.J., COWEN, P. J. (1987). Diazepam alters brain 5-HT function in man: Implications for the acute and chronic effects of benzodiazepines. Psychological Medicine (in press).Google Scholar
  5. 5).
    VAN PRAAG, H. M., LEMUS, C., KAHN, R. (1986). The pitfalls of serotonin precursors as challengers in hormonal probes of central serotonin activity. Psychopharmacology Bulletin 22: 565–570.PubMedGoogle Scholar
  6. 6).
    COWEN, P.J. (1987). Psychotropic drugs and human 5-HT neuroendocrinology. Trends Pharmac. Sci. 8: 105–108.CrossRefGoogle Scholar
  7. 7).
    McCANCE, S. L., COWEN, P. J., WALLER, H., GRAHAME-SMITH, D. G. (1987). The effect of metergoline on endocrine responses to L-tryptophan. Journal of Psychopharmacology (in press).Google Scholar
  8. 8).
    GOODWIN, G. M., FAIRBURN, C. G., COWEN, P. J. Dietary changes serotonergic function in women not men: implications for the aetiology of anorexia nervosa. Psychological Medicine (in press).Google Scholar
  9. 9).
    COWEN, P. J., CHARIG, E. M. (1987). Neuroendocrine responses to intravenous tryptophan in major depression. Archives General Psychiat. (in press).Google Scholar
  10. 10).
    HENINGER, G. R., CHARNEY, D. S., STERNBERG, D. E. (1984). Serotonergic function in depression: prolactin response to intravenous tryptophan in depressed patients and healthy subjects. Arch. Gen. Psychiat. 41: 398–402.PubMedGoogle Scholar
  11. 11).
    SIEVER, L. J., MURPHY, D. L., SLATER, S., DE LA VEGA, E., LIPPEN, S. (1984). Plasma prolactin following fenfluramine in depressed patients compared to controls: an evaluation of central serotonergic responsivity in depression. Life Sci. 34: 1029–1039.PubMedCrossRefGoogle Scholar
  12. 12).
    TAKAHASHI, S., KONDO, H., YOSHIMURA, M., OCHI, Y., YOSHIMI, T. (1973). Growth hormone responses to administration of L-5-hydroxytryptophan (L-5-HTP) in manic depressive psychoses. Folia Psychiatrica Neurologica Japonica 27: 197–206.Google Scholar
  13. 13).
    MELTZER, H. Y., PERLINE, R., TRICOU, P. J., LOWY, M., ROBERTSON, A. (1984). Effect of 5-hydroxytryptophan on serum cortisol levels in major affective disorders: 1. Enhanced response in depression and mania. Arch. Gen. Psychiat. 41: 366–374.PubMedGoogle Scholar
  14. 14).
    MELTZER, H. Y., PERLINE, R., TRICOU, B. J., LOWY, M., ROBERTSON, A. (1984). Effect of 5-hydroxytryptophan on serum cortisol levels in major affective disorders: 2. Relation to suicide, psychosis and depressive symptoms. Arch. Gen. Psychiat 41: 379–387.PubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1988

Authors and Affiliations

  • P. J. Cowen
    • 1
  1. 1.MRC Unit of Clinical Pharmacology and University Department of PsychiatryLittlemore HospitalOxfordEngland

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