| Abstrakt: |
Summary.Adenylate cyclase activity was measured in broken cell preparations of whole endometrial tissue from rabbits on Days 0, 1, 6·5, 9 and 15 of pseudopregnancy and in endometrial epithelial and stromal cells on Days 1 and 6·5 to assess the specific response of individual cell types. In dispersed cells, adenylate cyclase activity was higher (P< 0·01) in stromal than in epithelial cells and reduced on Day 6·5 compared to Day 1 in both cell types. The response of adenylate cyclase to isoproterenol appeared more important relative to the PGE-2 response in epithelial than in stromal cells and strongly reduced in the former on Day 6·5. In endometrium, the overall adenylate cyclase activity was increased significantly on Day 1 of pseudopregnancy compared to Day 0 (oestrus), only 18 h after injection of hCG. On the following days, the activity decreased progressively on Days 6·5 and 9 and exhibited a recovery on Day 15. Adenylate cyclase response to isoproterenol (% over GTP) was comparable on Days 0, 1 and 6·5, abolished on Day 9 and recovered on Day 15. Maximal response to PGE-2 (% over GTP) was observed on Day 6·5, at the time of implantation, maintained on Day 9 and reduced on Day 15 towards the low levels measured in oestrus and Day 1 of pseudopregnancy. Our results demonstrate a dramatic alteration of adenylate cyclase activity in rabbit endometrium during pseudopregnancy. It suggests a possible involvement of catecholamines and prostaglandin E-2 in the regulation of endometrial receptivity through a cAMP-mediated process.Keywords:endometrium; prostaglandins; cyclic AMP; catecholamines; decidual reaction |
