Sex-related difference in the release of dopamine into hypophysial portal blood

G. A. Gudelsky, J. C. Porter

Research output: Contribution to journalArticle

65 Scopus citations

Abstract

The concentration of dopamine (DA) in pituitary stalk plasma of cycling female rats during diestrus was approximately 7 times that in stalk plasma of intact male rats, and the rate of DA synthesis in the median eminence of diestrous female rats was 5 times that in the median eminence of intact male rats. DA concentrations in pituitary stalk plasma of castrated adult male rats, orchiectomized as adults or as 1-day-old neonates, did not differ significantly from those of intact adult male rats. However, treatment of male rats with 17β-estradiol benzoate for 3 days resulted in a significant (P > 0.005) increase in the concentration of DA in pituitary stalk plasma. DA concentrations in stalk plasma of adult female rats, ovariectomized as adults or treated with testosterone propionate (50 g) on day 1 of life, did not differ appreciably from those of diestrous female rats. However, DA concentrations in stalk plasma of adult female rats that had been ovariectomized on day 14 of life were significantly (P > 0.01) lower than those of diestrous female rats. In view of these results, it is concluded 1) that there is a sex-related difference in the release of DA from tuberoinfundibular neurons into hypophysial portal blood, and 2) that this difference is not due to a suppressive action of androgen on the secretion of DA in the male rat, but is a consequence of a stimulatory action of estrogen on the release of DA in the female rat.

Original languageEnglish (US)
Pages (from-to)1394-1398
Number of pages5
JournalEndocrinology
Volume109
Issue number5
DOIs
StatePublished - Nov 1981

ASJC Scopus subject areas

  • Endocrinology

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