17-beta-Estradiol upregulates COX-2 in the rat oviductReport as inadecuate




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We investigated the regulation of cyclooxygenase-2 COX-2 by 17-beta-estradiol E-2 in the rat oviduct. We observed that COX-2 is expressed mainly in proestrous and estrous stages, periods under estrogenic influence. While exogenous administration of E2 1 mu g-rat significantly increased COX-2 protein levels, progesterone did not modify it. COX-2 was mainly localized on oviductal. epithelial cells from estrogenized rat. Induction of COX-2 expression by E-2 was partially reverted by tamoxifen 1 mg-rat, an E-2 receptor antagonist. Estradiol treatment also increased prostaglandins PGs synthesis: 6-keto-PGF1 alpha 40%, a stable metabolite of prostacyclin PGI2, PGF2 alpha 40% and PGE2 50%. Tamoxifen completely suppressed this enhancement. In order to discriminate which isoform of COX was implicated in the stimulatory effect of E-2 on PGs synthesis, oviducts were preincubated with meloxicam Melo: 10-9 M or NS-398 10-7 M, two selective COX-2 inhibitors. Both Melo and NS-398 abolished the increase of PGs synthesis stimulated by E-2. All together, these data indicate that E-2 could upregulate COX-2 expression and activity in the rat oviduct and that the stimulatory effect of E-2 may be receptor-mediated.



Author: Pérez Martínez, S.; - Hermoso Ramello, Marcela; - Farina, M.; - Ribeiro, M. L.; - Rapanelli, M.; - Espinosa, M.; - Villalón Ca

Source: http://repositorio.uchile.cl/



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