[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 E2 (PGE2) 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 PGE2 in a dose dependent manner in the range between 10 pmol/L and 10 nmol/L. The inhibitory effect grew stronger as the time of pretreatment extended. Adenylate cyclase activity induced by PGE2 was significantly reduced in the cells pretreated with dexamethasone.

CONCLUSION

The results strongly suggest that dexamethasone inhibits cAMP production induced by PGE2 in cultured aortic smooth muscle cells and the inhibitory effect is exerted at the level of adenylate cyclase. In addition, the inhibitory effect of PGE2 on cultured smooth muscle cell proliferation was resisted by dexamethasone, anyhow no direct enhancing effect on cell proliferation by dexamethasone was detected.