Type 2 and 5 17beta-hydroxysteroid dehydrogenases and androgen receptor in human fetal lungs.

Androgens delay fetal lung maturation through an androgen receptor (AR)-dependent mechanism. Type 2 and 5 17beta-hydroxysteroid dehydrogenases (17betaHSD) are involved in androgen inactivation and synthesis, respectively. We aimed to further characterize the human fetal lung potential for androgen metabolism and response. 17betaHSD2, 17betaHSD5, and AR mRNA levels were determined in lungs of mid-late gestation and in adult lungs, while protein detections were performed at mid-gestation. Relationships between levels of each mRNA and gestational age were observed. AR protein levels showed important differences among individuals of the same gestational window. 17betaHSD2 and AR were co-localized in epithelial and mesenchymal cells. AR was detected in both, cytoplasm and nucleus, which suggests fine-tuning of AR occupancy. In contrast, 17betaHSD5 was localized in a few epithelial cells of conducting zones. Our results support the existence of a local androgen metabolism in male and female human fetal lungs during the period of high-risk premature birth.