Gestation-related and betamethasone-induced changes in 11beta-hydroxysteroid dehydrogenase types 1 and 2 in the baboon placenta.
OBJECTIVE
We determined developmental and labor-related changes in 11beta-hydroxysteroid (HSD) 1 and 2 expression in baboon placentas during the final third of gestation and labor. We examined whether maternal glucocorticoid administration alters placental 11beta-HSD 2 expression.


METHODS
Maternal and fetal plasma cortisol concentrations were measured in five animals. Types 1 and 2 11beta-HSD messenger RNA (mRNA) and protein in placentas obtained at 121 to 185 days' gestation (dGA, term approximately 185 dGA, n = 16), during labor between 141 and 193 dGA (n = 8), and after maternal administration of four doses of 87.5 microg/kg betamethasone (n = 5) at 12-hour intervals at 121 to 135 dGA were analyzed by Northern and Western blot.


RESULTS
Cortisol levels were higher in maternal plasma than fetal (4-fold, P <.mob031). Placental 11beta-HSD 2 mRNA and protein decreased after 0.9 gestation (P <.001). 11beta-HSD 1 mRNA remained unchanged. There was no effect of labor on placental 11beta-HSD 1 and 2 mRNA and protein levels. Maternal betamethasone administration dramatically increased (P <.05) 11beta-HSD 2 mRNA as well as protein without effect on 11beta-HSD 1 mRNA and protein expression.


CONCLUSIONS
The late-gestation baboon maternal plasma cortisol concentration is four times the fetal plasma concentration. Decreased placental 11beta-HSD 2 may enhance maternal cortisol passage to the fetus at the end of gestation, thereby contributing to cortisol-mediated changes within the placenta and cortisol in fetal plasma at this stage of fetal development. The positive effect of betamethasone on placental 11beta-HSD 2 induction further suggests an ability of the placenta to regulate glucocorticoid transfer in the presence of elevated maternal glucocorticoid.
Ma
Xiao Hong
XH
Laboratory of Pregnancy and Newborn Research, Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Wu
Wen Xuan
WX
Nathanielsz
Peter W
PW
D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; D000818:Animals; D001623:Betamethasone / Q000494:pharmacology*; D015152:Blotting, Northern; D015153:Blotting, Western; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D005865:Gestational Age; D005938:Glucocorticoids / Q000494:pharmacology*; D006854:Hydrocortisone / Q000097:blood; D006913:Hydroxysteroid Dehydrogenases / Q000032:analysis* / Q000235:genetics; D007743:Labor, Obstetric / Q000502:physiology; D010215:Papio; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis
D005938:Glucocorticoids; D012333:RNA, Messenger; D001623:Betamethasone; D006913:Hydroxysteroid Dehydrogenases; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; D006854:Hydrocortisone