17beta-hydroxysteroid dehydrogenase type 1 and 2 expression in the human fetus.

Journal of Clinical Endocrinology and Metabolism

PubMedID: 10634418

Takeyama J, Suzuki T, Hirasawa G, Muramatsu Y, Nagura H, Iinuma K, Nakamura J, Kimura KI, Yoshihama M, Harada N, Andersson S, Sasano H. 17beta-hydroxysteroid dehydrogenase type 1 and 2 expression in the human fetus. J Clin Endocrinol Metab. 2000;85(1):410-6.
The present study investigates the expression patterns of 17beta-hydroxysteroid dehydrogenase (17betaHSD) isozymes in human fetal tissues to understand how estrogenic activity is regulated in the human fetus. Using enzyme assay, high 17betaHSD activity was detected in the placenta and liver, and low levels of 17betaHSD activity were also present in the gastrointestinal tract and kidney. After Northern blot analysis, we detected the messenger ribonucleic acid for 17betaHSD type 1 (17betaHSD1) only in the placenta, whereas that for 17betaHSD type 2 (17betaHSD2) was detected in the placenta, liver, gastrointestinal tract, and urinary tract at 20 gestational weeks. In RT-PCR analysis of the messenger ribonucleic acid transcripts, 17betaHSD 1 was predominantly expressed in the placenta, brain, heart, lung, and adrenal, whereas 17betaHSD2 expression was predominantly detected in the liver, gastrointestinal tract, and kidney. In addition, we detected 17betaHSD2 immunoreactive protein in surface epithelial cells of the stomach, absorptive epithelial cells of the small intestine and colon, hepatocytes of the liver, and interstitial cells surrounding the urinary tubules of the renal medulla. 17betaHSD2 in these tissues may be functioning in the prevention of in utero exposure of the fetus to excessive estradiol from the maternal circulation and amniotic fluids.