Expression of a cytosolic phospholipase A2 by ovine endometrium on days 11-14 of a simulated oestrous cycle

Abstract

Oxytocin stimulates the synthesis and secretion of PGF2\g=a\ from uterine tissues in vivo and in vitro late in the ovine oestrous cycle. The synthesis of eicosanoids is dependent upon the availability of free arachidonic acid which is released through the activity of arachidonate releasing phospholipases. In the present study, the following hypothesis was tested: the ovine endometrium expresses a cytosolic phospholipase A2 (cPLA2)

Interferon-Tau Suppresses Prostaglandin F2α Secretion Independently of the Mitogen-Activated Protein Kinase and Nuclear Factor κ B Pathways1

“…This finding is consistent with results reported by Binelli et al [30] in that it took about 12 h of culture with rbIFN-to notice inhibitory effects on PLA 2 . In the present experiments, cultures were terminated within 5 h. Graf et al [47] showed similar results for PLA 2 mRNA expression in the ewe upon treatment with oxytocin. We also investigated the phosphorylation of Raf-1 and ERK-1/2.…”

An in vitro investigation of the actions of reproductive hormones on the cervix of the ewe in the follicular stage: The effects of 17β-estradiol, oxytocin, FSH, and arachidonic acid on the cervical pathway for the synthesis of prostaglandin E2

“…Our previous studies have shown that there were increased levels of estradiol receptor a, OTR, cPLA 2 , and COX-2 in the ovine cervix during the periovulatory period of the estrous cycle [18]. These observations are consistent with those of other groups who have also reported high levels of these proteins during the periovulatory period in the cervix [14,[19][20][21] or uterus [22] and provide evidence to support our hypothesis that the reproductive hormones (17b-estradiol, FSH, and oxytocin) collectively regulate cervical relaxation by stimulating COX-2-mediated synthesis of cervical PGE 2 .…”

“…Lysates of incubated cervical tissue gave a single band at approximately 100 to 110 kDa corresponding to the molecular weight of ovine cytosolic PLA 2 [22]. There were no significant differences in the expression of cPLA 2 among control explants and those treated with either FSH or 17b-estradiol (Fig.…”

Mecanismos endócrinos e moleculares pelos quais o estradiol estimula a síntese de prostaglandina F2α no endometrial em fêmeas bovinas

“…-DESNOYERS et al, 1995;TYSSELING et al, 1998;ARNOLD et al, 2000; experimento 2 da presente tese). Em outros estudos a tapsigargia, um potente inibidor da atividade cálcio APTase, estimulou a síntese de PGF2α em explantes endometriais bovinos (TYSSELING et al, 1998;BURNS;HAYES;SILVIA, 1998) JORGE et al, 2003) e 18° dias do ciclo estral (RICO et al, 1981;KNICKERBOCKER et al, 1982). Assim, sugere-se que a síntese de PGF2α estimulada pelo E 2 , estaria na dependência de outros fatores endógenos presentes no organismo animal, condição que não seria reproduzida em um sistema de cultivo de células, uma vez que os demais fatores endógenos estariam ausentes.…”

“…O elemento de resposta típico contém 5'-GGTCAnnnTGACC-3' como a seqüência de nucleotídeos necessária para que haja a ativação da transcrição do gene em resposta ao estradiol (DRISCOL et al, 1998). -DESNOYERS et al, 1995;BURNS et al, 1997;BURNS;HAYES;SILVIA, 1998;MANN, 2001 FAGAN;GOLBERG, 1986;GOFF, 1990;SLAMA;VAILLANCOURT;GOFF, 1994 Antes de iniciar os ensaios preparar uma planilha contendo o número dos tubos com a identificação dos conteúdos. As amostras devem ser divididas eqüitativamente entre os ensaios equivalente a um determinado experimento, animais e número da amostra de plasma coletada em série dentro de um mesmo ensaio.…”