Lack of effect of various endocrine manipulations on tryptophan hydroxylase activity of individual nuclei of the hypothalamus, limbic system, and midbrain of the rat

J. S. Kizer, M. Palkóvits, I. J. Kopin, J. M. Saavedra, M. J. Brownstein

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The tryptophan hydroxylase activity of individual nuclei of the limbic system, hypothalamus, and midbrain was determined after various endocrine manipulations in an attempt to identify specific endocrine responsive serotonergic structures in the rat brain. Following adrenalectomy, thyroidectomy, castration, or treatment with pharmacological doses of dexamethasone, testosterone, or thyroxine, no changes in tryptophan hydroxylase activity occurred in any of the areas of brain examined. Furthermore, in large sections of the hypothalamus and midbrain, total tryptophan hydroxylase activity was unaltered, and no changes in Km for substrate or co factor were found after adrenalectomy. This study, therefore, has failed to detect any hormonally responsive tryptophan hydroxylase activity in the rat brain. These findings suggest that endocrine induced alterations in serotonin turnover, if they occur, do so without measurable changes in the activity or kinetic properties of tryptophan hydroxylase.

Original languageEnglish
Pages (from-to)743-747
Number of pages5
JournalEndocrinology
Volume98
Issue number3
Publication statusPublished - 1976

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Tryptophan Hydroxylase
Limbic System
Mesencephalon
Hypothalamus
Adrenalectomy
Brain
Castration
Thyroidectomy
Thyroxine
Dexamethasone
Testosterone
Serotonin
Pharmacology

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Lack of effect of various endocrine manipulations on tryptophan hydroxylase activity of individual nuclei of the hypothalamus, limbic system, and midbrain of the rat. / Kizer, J. S.; Palkóvits, M.; Kopin, I. J.; Saavedra, J. M.; Brownstein, M. J.

In: Endocrinology, Vol. 98, No. 3, 1976, p. 743-747.

Research output: Contribution to journalArticle

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