Expression of 11 p-Hydroxysteroid Dehydrogenase: DISCUSSION(4)
The presence of GR mRNA confirms isolated granulosa cells and CL as G target tissues. Glucocorticoids or synthetic G, dexamethasone, has been shown to increase FSH-stimulated progesterone (P) production in cultured immature granulosa cells. This is at least partially due to a selective increase in 3 pHSD activity and a decrease in 20aHSD activity. Glucocorticoids also synergistically enhance FSH-, GnRH-, and epidermal growth factor-stimulated tissue-type plasminogen activator (tPA) activity and gene expression. These results are different from those of an early study in which an inhibitory effect of G on basal and FSH-stimulated tPA activity was shown in immature granulosa cells. The reason for the discrepancy between these studies is not clear. ampicillin antibiotic
An inhibitory effect of G was reported on FSH-stimulated aromatase activity and LH receptor levels. G appears to inhibit induction of aromatase, since it did not inhibit aromatase activity in mature granulosa cells. Overall, these results indicate that G enhances FSH-stimulated P production and tPA activity, without inhibiting already existing aromatase activity, while it inhibits induction of aro-matase and LH receptor in rat granulosa cells. The G receptor may also act as a P receptor. It has been reported that P inhibits 20aHSD expression in rat CL through GR. However, it has not yet been investigated whether P exerts any physiological effect through GR in granulosa or thecal-interstitial cells. Since GR is expressed constitutively throughout follicular development and luteinization, the differential expression of 11pHSD1 reductase and 11pHSD2 dehydrogenase observed in the present study may act as a key mechanism to control G action during follicular development.