Correlation in inflammatory fibroblasts between the number of glucocorticoid receptors and PGE2 release.
The anti-inflammatory effects of glucocorticoids are mediated through steroid receptor occupancy and there is a significant correlation between the extent of receptor saturation and the extent of the biological effects. In a previously published study, we found that the number of these receptors was higher in inflammatory fibroblasts than in quiescent ones. PGE2 release, measured at the same time as the number of steroid receptors, was higher when the cells were from inflammatory tissue. Our aim, in the present study, was to determine whether the PGE2 released by cells during inflammatory processes could participate in increasing the number of steroid receptors. Fibroblasts obtained from rat quiescent subcutaneous connective tissue and granulomas were subcultured in monolayers. The specific binding of [3H]dexamethasone was assessed and analyzed by a method described by Kalimi et al. After a freeze-thaw cycle, we observed a decrease in the number of receptors in inflammatory fibroblasts. When the frozen and thawed fibroblasts were subcultured in the presence of PGE2 (10(-8) M), the number of receptors was enhanced in fibroblasts from inflammatory tissue. Cycloheximide (3 X 10(-7) M) prevented this increase. The release of PGE2 decreased after freezing and then increased simultaneously with the number of receptors in inflammatory cells. These findings suggest that PGE2 may play a role in regulating steroid effects on fibroblast function.
D000818:Animals; D002478:Cells, Cultured; D003238:Connective Tissue / Q000502:physiology; D003239:Connective Tissue Cells; D003907:Dexamethasone / Q000378:metabolism; D015237:Dinoprost; D015232:Dinoprostone; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology*; D007249:Inflammation; D008297:Male; D011458:Prostaglandins E / Q000378:metabolism*; D011460:Prostaglandins F / Q000378:metabolism; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000378:metabolism*
D011458:Prostaglandins E; D011460:Prostaglandins F; D011965:Receptors, Glucocorticoid; D003907:Dexamethasone; D015237:Dinoprost; D015232:Dinoprostone