Expression and localization of PPARs in the rat ovary during follicular development and the periovulatory period

Carolyn M. Komar, Olivier Braissant, Walter Wahli, Thomas E. Curry

Research output: Contribution to journalArticlepeer-review

129 Scopus citations

Abstract

PPARs are a family of nuclear hormone receptors involved in various processes that could influence ovarian function. We investigated the cellular localization and expression of PPARs during follicular development in ovarian tissue collected from rats 0, 6, 12, 24, and 48 h post-PMSG. A second group of animals received human CG (hCG) 48 h post-PMSG. Their ovaries were removed 0, 4, 8, 12, and 24 h post-hCG to study the periovulatory period. mRNAs corresponding to the PPAR isotypes (α, δ, and γ) were localized by in situ hybridization. Changes in the levels of mRNA for the PPARs were determined by ribonuclease protection assays. PPARγ mRNA was localized primarily to granulosa cells, and levels of expression did not change during follicular development. Four hours post-hCG, levels of mRNA for PPARγ decreased (P < 0.05) but not uniformly in all follicles. At 24 h post-hCG, levels of PPARγ mRNA were reduced 64%, but some follicles maintained high expression. In contrast, mRNAs for PPARα and δ were located primarily in theca and stroma, and their levels did not change during the intervals studied. To investigate the physiologic significance of PPARγ in the ovary, granulosa cells from PMSG-primed rats were cultured for 48 h with prostaglandin J2 (PGJ2) and ciglitazone, PPARγ activators. Both compounds increased progesterone and E2 secretion (P < 0.05). These data suggest that PPARγ is involved in follicular development, has a negative influence on the luteinization of granulosa cells, and/or regulates the periovulatory shift in steroid production. The more general and steady expression of PPARs α and δ indicate that they may play a role in basal ovarian function.

Original languageEnglish
Pages (from-to)4831-4838
Number of pages8
JournalEndocrinology
Volume142
Issue number11
DOIs
StatePublished - 2001

ASJC Scopus subject areas

  • Endocrinology

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