Expression of 11 p-Hydroxysteroid Dehydrogenase: DISCUSSION(5)
We find that in addition to GR, the rat ovary expresses MR mRNA. Coexpression of MR and 11 (3HSD2 is a feature of M target organs such as kidney and colon. Coordinate regulation of both genes in the ovary suggests that it may also be an M target organ. However, there is no known physiological role for M in the regulation of ovarian function. Aldosterone has been shown to modulate FSH-induced differentiation of rat granulosa cells in vitro, but this effect is likely to be due to action via GR. Mineralocorticoids serve physiological roles via association with MR to regulate fluid dynamics in classic M targets, where 11 pHSD2 is expressed to ensure inactivation of glucocorticoids that would otherwise inappropriately activate MR. Whether MR plays a similar role in the developing follicle remains to be determined. Buy Advair Diskus Online
The physiological importance of these results lies in the fact that the ovarian follicle is likely to operate a cortisol/ cortisone (corticosterone/11-dehydrocorticosterone in the rat) shuttle based on the differential expression of 11 pHSD isoforms, similar to that shown to operate in other G and M target tissues. Although ovaries do not undertake de novo corticosteroid synthesis due to lack of expression of the cytochrome P450s that catalyze C21 (P450C21) and C11 (P450C11p) hydroxylation, they clearly undertake corticosteroid metabolism.