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Title: EXPRESSION OF PEROXISOME PROLIFERATOR ACTIVATED RECEPTOR (PPAR) IS ASSOCIATED WITH SPECIFIC STAGES OF FOLLICULAR CELL DIFFERENTIATION IN PORCINE OVARIES

Author
item SCHOPPEE, P - U VA SCHOOL OF MEDICINE
item Guthrie, Howard
item VELDHUIS, J - U VA SCHOOL OF MEDICINE

Submitted to: Biology of Reproduction Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/8/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Activation of peroxisome proliferator activated receptor (PPAR), in response to its natural ligand 15-deoxy-delta-12,14-prostaglandin J2 induces cytodifferentiation in numerous cell types. We hypothesized that differentiation of follicular cells requires PPAR expression. Immunohistochemistry was performed on paraffin-embedded ovarian tissue containing follicles at different stages of development (primordial to Graafian before and after an LH surge) or mid-phase corpora lutea. PPAR expression varied with stage of development and with the health of individual follicles. The oocyte or the squamous pregranulosa cells in some primordial and transitional primary follicles stained positive for PPAR. Cumulus oophorus cells were consistently positive in healthy tertiary follicles, whereas the TC, mural GC and the oocyte were negative. Following the LH surge, PPAR became evident in mural GC and interna TC of preovulatory follicles. In atretic follicles, PPAR was detected in the oocyte and in some GC. The small luteal cells in healthy corpora lutea were positive for PPAR and large luteal cells were negative. Regressing corpora lutea contained macrophage-like cells that stained intensely for PPAR. Throughout the ovary, vascular endothelial cells possessed the most intense positive PPAR signal. In conclusion, PPAR was detected during 4 primary phases of follicular cell differentiation: 1) when oocytes expanded and squamous GC entered the active growth phase; 2) when GC differentiated into cumulus oophorus cells; 3) when TC and GC differentiated into luteal cells after the LH surge; and 4) when atretic oocytes and GC underwent terminal differentiation. These observations support our hypothesis that PPAR is essential to follicular cell cytodifferentiation.