THE TISSUE DISTRIBUTION OF PORCINE 17-BETA-ESTRADIOL DEHYDROGENASE AND ITS INDUCTION BY PROGESTERONE

Porcine 17 beta-estradiol dehydrogenase (EDH) was recently purified an d cloned. It catalyzes the NAD(+)-dependent oxidation of estradiol to estrone 360-fold more efficiently than the back reaction with NADPH. T he 32 kDa EDH is cut from an 80 kDa primary translation product with a multidomain structure unknown for other hydroxysteroid dehydrogenases . The highest EDH activities and strongest immunoreactions are found i n liver (hepatocytes) and kidney (proximal tubuli) followed by uterus (luminal and glandular epithelium), lung (bronchial epithelium). Proge sterone treatment of ovariectomized gilts stimulates oxidative EDH act ivity in uterus, anterior pituitary, skeletal muscle (diaphragm) and k idney. Constitutive levels of EDH activity were seen in the adrenals, the lung and the liver.