PARENT SESSION

(T635) ONTOGENY OF ESTROGEN AND ANDROGEN RECEPTOR EXPRESSION IN PORCINE SERTOLI CELLS: EFFECT OF REDUCING LOCAL TESTICULAR ESTROGEN SYNTHESIS USING AN AROMATASE INHIBITOR.

Ramesh, Revathi¹, Berger, Trish ¹, At-Taras, Eeman ¹, Pearl, Chris ¹, Conley, Alan¹, Roser, Janet¹, ¹ University of California, Davis, CA

ABSTRACT- Previous data suggests depressing estrogen synthesis during postnatal development using Letrozole, an aromatase inhibitor, increased Sertoli cell proliferation and delayed Sertoli cell maturation/puberty in pigs. The objective of the current study was to examine effects of this aromatase inhibition on androgen receptor (AR), estrogen receptor (ER) and estrogen receptor (ER) on Sertoli cells. One member of each littermate pair of boars was treated continuously with the aromatase inhibitor beginning at 1 week of age and the other member was treated with vehicle. Four different littermate pairs of boars were evaluated at 2, 3, 4, 5, 6, 7, and 8 months of age for AR, ER and ER expression by immunocytochemistry following antigen retrieval. Tissues from two 1–week old boars were also examined. Expression of AR, ER and ER were readily detected in Sertoli cells at 1 week of age. Although still present, immunolabeling of Sertoli cells with AR in the vehicle–treated animals was reduced at 2, 3, and 4 months of age. Sertoli cells from Letrozole–treated animals appeared to have more AR than littermate controls at these ages. AR immunolabeling was more prominent in the 6–8 month old animals and differences between vehicle and Letrozole–treated animals were not detectable with immunocytochemistry. Treated and vehicle–control animals exhibited similar immunolabeling for ER with Sertoli cells from younger animals prominently labeled and Sertoli cells from the older animals exhibiting lower expression. Sertoli cells also exhibited ER immunolabeling. In contrast to ER, Sertoli cells from the older males exhibited prominent labeling with ER antisera. Alteration of ER and AR immunolabeling of porcine Sertoli cells during postnatal development is similar to that described for the rat. These data indicate that inhibition of aromatase prevented the neonatal decline in Sertoli cell AR expression observed in control animals, suggesting that steroid products of aromatase are important mediators of testicular differentiation in pigs. (Supported in part by USDA NRICGP).

KEY WORDS: sertoli, sus scrofa, testes