Abstract
Progesterone (P4) is mandatory for maintenance of pregnancy in cattle. It can mediate its effects by binding to nuclear progesterone receptors (PGR) or through interaction with membrane-bound receptors. Two of those are the progesterone receptor membrane components (PGRMC)1 and 2. The distribution patterns of both receptors have been examined in different female reproductive tissues, but there is little data about their presence in the bovine uterus and placentomes during pregnancy. Therefore, the aim of this study was to demonstrate the cellular localization, mRNA and protein expression of PGRMC1 and 2 in both kinds of tissue during pregnancy. Tissue from 45 cows (n=5 per month of pregnancy) were investigated. There was a specific distribution pattern in the cellular localization: in the uterus both receptors were detected in cells of luminal and glandular epithelium, in endothelia of blood vessels and in placentomes in the maternal epithelium and stroma as well as in the endothelia of fetal and maternal blood vessels. PGRMC2 was also present in the chorionic epithelium. There were no variations in the mRNA- and protein expression patterns observed throughout gestation, neither in the uterus, nor in the placentomes. The incidence of these potential receptors and the specific cellular localisation suggests that PGRMCs are probably involved in nongenomic action of P4 in bovine uterus and placentomes during pregnancy.
Beyer, Nora Maria