Effects of in vivo pretreatment with D-Trp-6-LH-RH on prolactin and LH secretion by pituitary glands in vitro

I. Torres-Alemán, L. Debeljuk, A. V. Schally

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4 Scopus citations


In order to study a possible direct action of LH-RH analogs on the pituitary lactotrophs, we investigated the effect of long-term in vivo pretreatment with D-Trp-6-LH-RH on in vitro secretion of PRL and luteinizing hormone (LH) by the pituitary glands from male and female rats. In vivo pretreatment with D-Trp-6-LH-RH (50 μg/day, SC) for 15 days greatly reduced basal in vitro PRL release (p<0.01) in female, but not in male pituitary glands. TRH-stimulated PRL secretion was not affected by pretreatment with D-Trp-6-LH-RH in female rats, but was impaired in male pituitaries. Acute in vitro exposure to D-Trp-6-LH-RH did not modify PRL secretion by female pituitary glands pretreated in vivo with the analog. However, this same in vivo pretreatment greatly decreased PRL release from male pituitaries (p<0.01). Basal in vitro LH release by male pituitary glands was partially lowered by in vivo pretreatment with D-Trp-6-LH-RH, as compared to controls (p<0.01), while basal LH release in female pituitaries remained at control levels. Finally, D-Trp-6-LH-RH-induced stimulation of in vitro LH release was severely impaired in female pituitaries (p<0.01) but only slightly reduced in the males.

Original languageEnglish (US)
Pages (from-to)993-995
Number of pages3
Issue number5
StatePublished - Jan 1 1985
Externally publishedYes



  • Gonadotropins
  • In vitro
  • LH-RH analogs
  • Pituitary
  • Prolactin

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology
  • Physiology
  • Cellular and Molecular Neuroscience

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