Rat strain specific attenuation of estrogen action in the anterior pituitary gland by dietary energy restriction

Djuana M.E. Harvell, Linda K. Buckles, Karen A. Gould, Karen L. Pennington, Rodney D. McComb, James D. Shull

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The purpose of this study was to compare the effects of a 40% restriction of dietary energy consumption, relative to that consumed by rats allowed to feed ad libitum, on the ability of 17β-estradiol (E2) to induce pituitary tumorigenesis in two inbred rat strains, ACI and Copenhagen (COP), which are very closely related genetically. Ovary-intact ACI and COP rats were fed either a control or an energy-restricted diet beginning at 8 wk of age. Continuous treatment with E2, released from subcutaneous Silastic tubing implants, was initiated at 9 wk of age and the animals were killed 12 wk later. Estrogen-induced pituitary tumorigenesis is associated with rapid induction of lactotroph hyperplasia, increased pituitary mass, and hyperprolactinemia. E2 significantly increased pituitary mass and circulating prolactin (PRL) in both ACI and COP rats, and this response was significantly greater in ACI rats relative to COP. Dietary energy restriction did not inhibit E2-induced pituitary growth in the ACI rat. By contrast, E2-induced pituitary growth in COP rats was attenuated by dietary energy restriction, as evidenced by quantification of pituitary mass, pituitary weight to body weight ratio, circulating PRL, and pituitary cell proliferation. This study indicates that sensitivity to the inhibitory actions of dietary energy restriction on E2-induced pituitary tumorigenesis is genetically determined.

Original languageEnglish (US)
Pages (from-to)175-183
Number of pages9
JournalEndocrine
Volume21
Issue number2
DOIs
StatePublished - Jul 1 2003

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Keywords

  • ACI rat
  • COP rat
  • Estrogen
  • Lactotroph
  • Prolactin
  • Tumorigenesis

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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