The role of the suckling stimulus in regulating pituitary prolactin mRNA in the rat

Ling Ru Lee, Daniel J. Haisenleder, John C. Marshall, M (Susan) Smith

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Prolactin (PRL) gene expression and the synthesis and secretion of PRL were examined in ovarian-intact lactating rats suckling eight pups on 10 days postpartum. Plasma samples were assayed for PRL concentrations, and pituitary glands were analyzed for total PRL content and PRL mRNA levels. We found that suckling-induced hyperprolactinemia was associated with very high levels of plasma PRL and a doubling in pituitary PRL mRNA levels, whereas pituitary PRL content was not changed. Removal of the suckling pups decreased plasma PRL concentrations 15-fold within 24 h. This decrease in PRL secretion was not accompanied by any significant change in pituitary PRL content. Evidently, both synthesis and secretion of PRL were decreased in the pituitary gland within 24 h following cessation of suckling, as pituitary PRL mRNA content had returned to diestrous levels at this time. To determine whether or not ovarian steroids might have contributed to the changes in PRL synthesis and secretion during lactation and after withdrawal of the suckling stimulus, the experiments were repeated in lactating rats ovariectomized (OVX) on day 2 postpartum. The results in these OVX rats were qualitatively similar to those described in ovarian-intact rats. We concluded from these findings that the stimulus of suckling induces increases in PRL mRNA levels in the pituitary which provides for the increased PRL synthesis accompanying increased PRL secretion. The cessation of suckling led to prompt decreases in PRL synthesis and secretion within 24 h.

Original languageEnglish (US)
Pages (from-to)243-249
Number of pages7
JournalMolecular and Cellular Endocrinology
Volume64
Issue number2
DOIs
StatePublished - 1989
Externally publishedYes

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Prolactin
Rats
Messenger RNA
Pituitary Gland
Plasmas
Postpartum Period
Hyperprolactinemia
Lactation
Gene expression

Keywords

  • Lactation
  • Pituitary prolactin
  • Plasma prolactin
  • Prolactin mRNA

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

The role of the suckling stimulus in regulating pituitary prolactin mRNA in the rat. / Lee, Ling Ru; Haisenleder, Daniel J.; Marshall, John C.; Smith, M (Susan).

In: Molecular and Cellular Endocrinology, Vol. 64, No. 2, 1989, p. 243-249.

Research output: Contribution to journalArticle

Lee, Ling Ru ; Haisenleder, Daniel J. ; Marshall, John C. ; Smith, M (Susan). / The role of the suckling stimulus in regulating pituitary prolactin mRNA in the rat. In: Molecular and Cellular Endocrinology. 1989 ; Vol. 64, No. 2. pp. 243-249.
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