Estrogen Regulates 11β-Hydroxysteroid Dehydrogenase-1 and -2 Localization in Placental Syncytiotrophoblast in the Second Half of Primate Pregnancy

We recently demonstrated that the 11β-hydroxysteroid dehydrogenase enzymes catalyzing cortisol-cortisone reduction (11β-hydroxysteroid dehydrogenase-1) and oxidation (11β-hydroxysteroid dehydrogenase-2) are located in different regions of the baboon and human placental syncytiotrophoblast. Moreover, there was a 2-fold increase in the ratio of 11β-hydroxysteroid dehydrogenase-2 to 11β-hydroxysteroid dehydrogenase-1 in syncytiotrophoblast membranes contiguous with the basal membrane (BMm) between mid and late baboon gestation. Our laboratories have also shown that estrogen regulates syncytiotrophoblast functional differentiation. Therefore, the current study determined whether the change in the ratio of 11β-hydroxysteroid dehydrogenase-2 to 11β-hydroxysteroid dehydrogenase-1 in the BMm was regulated by estrogen. Placentas were obtained on d 165 of gestation (term = d 184) from baboons that were untreated or were treated daily beginning on d 100 with the aromatase inhibitor CGS 20267, which reduced uterine a...