RESUMO
Endothelin (EDN) is a possible regulating factor of oviductal motility, which is important for the transport of gametes and embryo. To clarify the factors that control the secretion of EDN in the bovine oviduct, the expression of EDNs, EDN-converting enzymes (ECEs) and EDN receptors (EDNRs) were investigated. All isoforms of EDN (EDN1-3), ECE (ECE1 and ECE2) and EDNR (EDNRA and EDNRB) were immunolocalised in the epithelial cells of the ampulla and the isthmus. EDNRs were also immunolocalised in smooth-muscle cells. The mRNA expression of EDN2 and ECE2 was higher in cultured ampullary oviductal epithelial cells than in isthmic cells. The expression of EDN1, EDN2 and ECE2 in the ampullary tissue was highest on the day of ovulation. Oestradiol-17ß increased EDN2 and ECE1 expression, while progesterone increased only ECE1 expression in cultured ampullary epithelial cells. These results indicate that EDNs are produced by epithelial cells and their target site is smooth-muscle and epithelial cells, and suggest that ovarian steroids are regulators of endothelin synthesis in ampullary oviductal epithelial cells.
Assuntos
Endotelina-1/metabolismo , Endotelina-2/metabolismo , Enzimas Conversoras de Endotelina/metabolismo , Tubas Uterinas/fisiologia , Mucosa/metabolismo , Músculo Liso/metabolismo , Receptor de Endotelina A/metabolismo , Matadouros , Animais , Animais Endogâmicos , Bovinos , Células Cultivadas , Endotelina-1/genética , Endotelina-2/genética , Endotelina-3/genética , Endotelina-3/metabolismo , Enzimas Conversoras de Endotelina/genética , Tubas Uterinas/citologia , Tubas Uterinas/enzimologia , Feminino , Regulação da Expressão Gênica , Imuno-Histoquímica/veterinária , Isoenzimas/genética , Isoenzimas/metabolismo , Mucosa/citologia , Mucosa/enzimologia , Músculo Liso/citologia , Músculo Liso/enzimologia , Especificidade de Órgãos , Ovulação/metabolismo , RNA Mensageiro/metabolismo , Receptor de Endotelina A/agonistas , Receptor de Endotelina B/agonistas , Receptor de Endotelina B/metabolismo , Transdução de SinaisRESUMO
Summer heat stress (HS) negatively affects reproductive functions, including prostaglandin (PG) F2α secretion in the endometrium, and decreases fertility in cattle. In the present study, we examined the effects of elevated temperatures on PG synthesis in oviductal epithelial cells. The epithelial cells obtained from the ampulla and isthmus of the oviduct were incubated at various temperatures (38.5, 39.5, 40.0, and 40.5â°C) for 24âh. In the ampulla, PGE2 concentration was higher at 40.5â°C than at 38.5â°C, while PGF2α production was not affected by the temperatures in this range. The expressions of microsomal PGE synthase 1 (PTGES (mPGES1)), cytosolic PGES (PTGES3 (cPGES)), and heat shock protein 90 (HSP90AA1 (HSP90)) mRNAs and proteins were higher at 40.5â°C than at 38.5â°C in the ampullary epithelial cells. Seasonal changes in the expressions of PGES and HSP90AA1 mRNAs in oviductal tissues were also investigated. The expressions of PTGES3 and HSP90AA1 mRNAs were higher in the ampullary tissues in summer than in winter. In summary, elevated temperatures stimulated PGE2 production in the ampullary oviduct by increasing the expressions of PGESs and HSP90AA1, which can activate cPGES. The overall results suggest that HS upsets PG secretions and reduces oviductal smooth muscle motility, which in turn could decrease gamete/embryo transport through the oviduct.
