Human amniotic membrane corticosteroid 11-oxidoreductase activity.
The ability of amniotic membrane, obtained with 3 h of delivery of 28 infants, to interconvert 3H-cortisol and 14-C-cortisone has been examined. The conversion of cortisone to cortisol increases as a function of gestational age, being first seen at 29.5 weeks and reaching values of 50--55% at term (n = 28, r = 0.615, P less than 0.01). Furthermore, a net gain of the active hormone (cortisol) resulting from the bidirectional interconversion of cortisol and cortisone ("C-11 activation index") appears at 31 weeks and reaches 40--50% by term (n = 28, r = 0.674, P less than .001). We speculate that this phenomenon could be an important source of active glucocorticoid for the fetus.
D000650:Amnion / Q000201:enzymology*; D002823:Chorion / Q000201:enzymology*; D003348:Cortisone / Q000378:metabolism*; D005260:Female; D005865:Gestational Age; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D006913:Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D011247:Pregnancy
D006913:Hydroxysteroid Dehydrogenases; D003348:Cortisone; D006854:Hydrocortisone