Expression and possible role of 20alpha-hydroxysteroid dehydrogenase in the placenta of the goat.
20Alpha-hydroxysteroid dehydrogenase (20alpha-HSD) catalyzes the conversion of progesterone to its inactive form 20alpha-dihydroprogesterone (20alpha-OHP). 20Alpha-HSD is expressed in the murine placenta, suggesting a role, yet unidentified, played by this enzyme during the course of pregnancy. To elucidate the possible roles of 20alpha-HSD during pregnancy, 20alpha-HSD gene expression in the placenta was examined by Northern blot analysis, and progestin (progesterone and 20alpha-OHP) concentrations in the maternal and fetal sera and the amniotic fluid were measured by radioimmunoassay in pregnant Shiba goats. The expression of 20alpha-HSD mRNA was observed in the placenta and the intercaruncular part of the uterus during mid to late pregnancy. Analysis by in situ hybridization revealed that 20alpha-HSD mRNA was mainly localized in the endometrial epithelium of the caruncle side of the placenta. Considerable enzyme activity of 20alpha-HSD was also detected in the cytosolic fraction of the placenta and intercaruncular part of the uterus. Although concentrations of progesterone and 20alpha-OHP in the maternal serum showed similar profiles, progesterone levels in the fetal serum stayed extremely low throughout the pregnancy. The 20alpha-OHP concentration in the fetal serum was always higher than that in the maternal serum. In the amniotic fluid, the concentrations of both progesterone and 20alpha-OHP remained at very low levels throughout the pregnancy. These results support the notion that 20alpha-HSD protects the fetus from the cytotoxic effects of progesterone, and thereby maintains the normal development of the fetus.
Jayasekara
Walimuni Samantha Nilanthi
WS
Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Japan.
Yonezawa
Tomohiro
T
Ishida
Maho
M
Yamanouchi
Keitaro
K
Nishihara
Masugi
M
D043607:20-alpha-Hydroxysteroid Dehydrogenase / Q000235:genetics* / Q000378:metabolism*; D000653:Amniotic Fluid / Q000378:metabolism; D000818:Animals; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D006041:Goats / Q000502:physiology*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D012333:RNA, Messenger / Q000032:analysis; D014599:Uterus / Q000201:enzymology
D012333:RNA, Messenger; D011374:Progesterone; D043607:20-alpha-Hydroxysteroid Dehydrogenase