Gonadotropin‐dependent regulation of the prostaglandin E2 receptor in equine preovulatory follicles during the ovulatory process in mares

Abstract

The objectives of the study were to clone the primary structure of the prostaglandin E2 receptor subtype 2 (PTGER2) cDNA and to characterize its regulation in equine follicles during gonadotropin-induced ovulation. Results from DNA isolation indicated that the equine PTGER2 cDNA encodes a predicted 353-amino acid protein, which is highly similar (76-85%) to known mammalian homologues. The regulation of PTGER2 was studied by semi-quantitative RT-PCR/Southern blot using preparations of theca interna and mural granulosa cells isolated from equine follicles 0-39 hr post-treatment with human chorionic gonadotropin (hCG). Results indicated that a significant increase of PTGER2 mRNA occurred at 24 and 39 hr post-hCG in granulosa cells, and 30 and 33 hr post-hCG in theca cells (P < 0.05). Immunohistochemical staining and immunoblotting performed on equine follicular samples showed a corresponding increase of PTGER2 protein in both cell types after treatment with hCG. Levels of PTGER2 mRNA were also high in uterus, thymus and spleen, but moderate to low in other tested tissues. In the ovary, the expression of PTGER4 mRNA was observed and predominantly occurred in granulosa cells, with highest abundance of transcripts observed at 12 and 39 hr post-hCG. Thus, this study reports for the first time in mares that the ovulatory process is accompanied by the gonadotropin-dependent up-regulation of PTGER2 and PTGER4, which may in turn regulate PGE2-mediated preovulatory effects.

Human chorionic gonadotropin-dependent up-regulation of epiregulin and amphiregulin in equine and bovine follicles during the ovulatory process

“…The semiquantitative analysis of EREG, AREG, ADAM17 and RPL7A (internal control gene) mRNA levels in equine tissues was performed using the OneStep RT-PCR System (Qiagen, Mississauga, Canada) as previously described [47,48], and sense (5 0 -TTC CAT CTT CTC CAA GCA GTT CTC-3 0 ) and anti-sense (5 0 -CAG ACT TGT GGC AAC GCT GGA TCC-3 0 ) primers specific for equine EREG (generating a DNA fragment of 440 bp), sense (5 0 -GCT GGA TTG GAT GTC AAT GAC ACC-3 0 ) and anti-sense (5 0 -TTA CTG TCA ACC ATG CTG TGA GTC-3 0 ) primers specific for equine AREG (generating a DNA fragment of 493 bp), sense (5 0 -CAC CGT GTG CTT GGA TCT TGG C-3 0 ) and anti-sense (5 0 -CTG TCA ACA CGA CTC TGA CGC-3 0 ) primers specific for equine ADAM17 (generating a DNA fragment of 624 bp), and sense (5 0 -ACA GGA CAT CCA GCC CAA ACG-3 0 ) and anti-sense (5 0 -GCT CCT TTG TCT TCC GAG TTG-3 0 ) primers specific for equine RPL7A (generating a DNA fragment of 516 bp). These primers were designed from published sequences of equine EREG (accession number: XM_001490281), equine AREG (accession number: XM_001489471), equine ADAM17 (accession number: XM_001918266) and equine RPL7A (accession number: AF508309).…”

Prostaglandin receptors (EP2 and EP4) and angiotensin receptor (AGTR2) mRNA expression increases in the oviducts of Nelore cows submitted to ovarian superstimulation

“…In the present study, we showed an upregulation of EP2 mRNA abundance in the ampulla and EP4 mRNA abundance in the infundibulum, as well as a tendency of EP2 mRNA levels to increase in the infundibulum of the oviduct from cows submitted to the P-36/eCG protocol. We suggest the exogenous eCG used in the P-36/eCG protocol upregulates the mRNA abundance of PGE 2 receptors, as observed by Sayasith et al (2009) and Segi et al (2003), who reported an upregulation of EP2 and EP4 due to a chorionic gonadotrophin (hCG) in the preovulatory follicles of mares and mice, respectively. Furthermore, we demonstrated the P-36 protocol tended to stimulate PGES expression compared to control group.…”

Effect of exogenous prostaglandin E2 administration on ovarian follicle growth and angiogenesis in rat with reference to pregnant mare serum gonadotrophin

“…Several studies demonstrated that gonadotrophic hormone administration induced the expression of COX2 and the production of PGE2 by the follicular cells of ovarian follicles [27][28][29][30][31]. These investigations delineated that gonadotrophic hormones affect the ovary through PGE2.…”