Dehydrogenase and oxoreductase activities of porcine placental 11beta-hydroxysteroid dehydrogenase.

Dehydrogenase (cortisol to cortisone) and oxoreductase (cortisone to cortisol) activities of porcine placental 11beta-hydroxysteroid dehydrogenase (11beta-HSD) were measured in tissue fragment cultures on day 75 of gestation. Dehydrogenase activity was over fivefold greater than oxoreductase activity (p < .001). There were positive linear associations (p < .01) between net dehydrogenase activity (dehydrogenase minus oxoreductase) and fetal weight, fetal length, and placental weight. These data indicate a predominance of placental 11beta-HSD dehydrogenase activity at this gestational stage that would insure a net conversion of cortisol to cortisone as it traverses the placenta. The data further suggest that 11beta-HSD activities may provide an optimal glucocorticoid environment that is supportive of enhanced fetal and placental growth.