Melatonin effects on prolactin secretion in pituitary-grafted female rats

A. I. Esquifino, M. A. Villanua, C. Agrasal, R. J. Reiter, J. A.F. Tresguerres

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Melatonin influences prolactin (PRL) secretion through unknown mechanisms. This work was undertaken to study the effects of melatonin administration of PRL secretion in pituitary-grafted female rats. Melatonin administration resulted in a marked and rapid decrease of previously high plasma PRL levels in pituitary-grafted rats. Luteinizing hormone releasing hormone (LHRH) administration resulted in a marked decrease of plasma PRL levels in both sham-operated and grafted animals given saline whereas a statistically significant increase was observed in grafted, mela-tonin-treated rats. Estradiol benzoate administration caused an increase in plasma PRL levels of greater magnitude in the afternoon than in the morning in sham-operated animals given saline whereas in grafted animals no response to estradiol benzoate was detected. Melatonin increased the plasma PRL response to estradiol benzoate in sham-operated rats as compared to vehicle-treated animals. A normalization of PRL response to estradiol benzoate was shown in melatonin-treated, pituitary grafed rats. While the suppressive effects of melatonin in plasma PRL levels of pituitary-grafted animals is substantial the mechanism of this inhibition remains unknown.

Original languageEnglish (US)
Pages (from-to)171-176
Number of pages6
JournalJournal of endocrinological investigation
Volume12
Issue number3
DOIs
StatePublished - Mar 1989

Keywords

  • Melatonin
  • female rats
  • pituitary grafts
  • prolactin

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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