糖皮质激素对前列腺素E2介导的主动脉平滑肌细胞cAMP生成的影响

目的观察地塞米松对前列腺素Ｅ２介导的离体培养兔主动脉平滑肌细胞的ｃＡＭＰ生成的影响。方法用蛋白竞争结合法测定细胞ｃＡＭＰ含量,并确定腺苷酸环化酶的活性。结果从１０ｐｍｏｌ／Ｌ到１０ｎｍｏｌ／Ｌ地塞米松对培养细胞的ｃＡＭＰ生成有明显抑制作用并呈现剂量依赖性,作用时间愈长,该抑制作用愈强。经地塞米松预处理８小时的培养细胞,其前列腺素Ｅ２介导的腺苷酸环化酶活性显著下降。结论糖皮质激素在腺苷酸环化酶水平抑制前列腺素Ｅ２介导的培养平滑肌细胞ｃＡＭＰ生成。另外还观察到地塞米松拮抗前列腺素Ｅ２的抑制培养细胞增生效应,但未发现地塞米松对培养平滑肌细胞增生的直接促进作用

Effects of dexamethasone on cAMP production induced by prostaglandin E2 in aortic smooth muscle cells

Objective To study the effects of dexamethasone on cAMP production induced by prostaglandin E 2 (PGE 2 )in cultured rabbit aortic smooth muscle cells.Methods cAMP concentration was determined by protein competition contact assay.Results Dexamethasone significantly inhibited cAMP accumulation induced by PGE 2 in adose dependent manner in the range between10pmol/Land 10nmol/L.The inhibitory effect grew stronger as the time of pretreatment extended.Adenylate cyclase activity induced by PGE 2 was significantly reduced in the cells pretreated with dexamethasone.Conclusion The results strongly suggest that dexamethasone inhibits cAMP production induced by PGE 2 in cultured aortic smooth muscle cells and the inhibitory effect is exerted at the level of adenylate cyclase. In addition,the inhibitory effect of PGE 2 on cultured smooth muscle cell proliferation was resisted by dexamethasone,anyhow no direct enhancing effect on cell proliferation by dexamethasone was detected.