To elucidate the role of estradiol- 17 (E2) in the regulation of corpus luteum function

Corpus luteum (CL) is a transient endocrine tissue formed from the remnants of the ovarian follicle after ovulation. In response to gonadotropin surge, the ovulating follicle undergoes dramatic changes in expression of genes and differentiation of follicular cells into luteal cells. In several species, of the several genes that are down- regulated post ovulation, Cyp19A1 that codes for aromatase, essential for biosynthesis of estradiol- 17 (E2), also get down- regulated but appears to get up- regulated at later time points in the estrous cycle to have critical role in E2 secretion. In primates and rodents, higher expression and higher E2 levels has been observed in CL. Surprisingly, in the recently carried out gene expression profiling of PGF2- induced luteolysis studies in the bovine species [GSE27961], it was observed that expression of one of the earliest genes that was down- regulated was Cyp19A1 in the CL. However, the specific role of E2 in the regulation of CL function remains poorly defined. Thus, in the present study, efforts were made to examine the temporal changes in the global gene expression profile in the CL of pregnant rats after treatment with aromatase inhibitor (AI), Anastrozole, and E2 supplementation. The results obtained will further expand our knowledge on E2 target/responsive genes and the basic mechanism(s) that regulates the CL function. Key words: CL, E2, AI, Gene expression

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