Effect of ovarian steroids to stimulate region-specific hypothalmic 5-hydroxytryptamine synthesis in ovariectomized rats

Thomas S King, R. W. Steger, W. W. Morgan

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Abstract

Accumulations of 5-hydroxytryptophan (5HTP) and L-dihydroxyphenylalanine (L-DOPA) following decarboxylase inhibition as indices for 5-hydroxytryptamine (5HT) and catecholamine (dopamine and/or norepinephrine) synthesis, respectively, were both increased in the preoptic area-anterior hypothalamus (POA-AH) of ovariectomized rats treated with a combination of 17β-estradiol benzoate (E2) and progesterone (P). Similarly, an increased accumulation of L-DOPA was seen in the mediobasal hypothalamus (MBH) and median eminence (ME) of these animals although no change was observed in 5HTP accumulation in the MBH or ME of these rats. Hypophysectomy negated these steroid-induced effects on L-DOPA accumulation. However, hypophysectomy had no apparent effect on steroid-stimulated 5HTP accumulation in the POA-AH of these rats. Under the experimental conditions of our study, the results suggest (1) that the stimulatory effect of ovarian steroids on hypothalamic catecholamine synthesis is dependent on an intact pituitary gland, (2) that the stimulatory effect of ovarian steroids on 5HT synthesis in the POA-AH is not dependent on an intact pituitary gland, and (3) that ovarian steroids do not seem to influence 5HT synthesis in the ME or MBH. The significance of these results may lie in the function of these hypothalamic monoaminergic neurotransmitter systems to regulate gonadotrophin release and subsequent steroid feedback modulation of such central regulatory mechanisms.

Original languageEnglish (US)
Pages (from-to)344-350
Number of pages7
JournalNeuroendocrinology
Volume42
Issue number4
StatePublished - 1986

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Serotonin
Steroids
Anterior Hypothalamus
5-Hydroxytryptophan
Median Eminence
Dihydroxyphenylalanine
Preoptic Area
Hypothalamus
Hypophysectomy
Pituitary Gland
Catecholamines
Carboxy-Lyases
Gonadotropins
Neurotransmitter Agents
Dopamine
Norepinephrine

ASJC Scopus subject areas

  • Endocrinology
  • Neuroscience(all)

Cite this

Effect of ovarian steroids to stimulate region-specific hypothalmic 5-hydroxytryptamine synthesis in ovariectomized rats. / King, Thomas S; Steger, R. W.; Morgan, W. W.

In: Neuroendocrinology, Vol. 42, No. 4, 1986, p. 344-350.

Research output: Contribution to journalArticle

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