Placental 17 beta-hydroxysteroid oxidoreductase, lactate dehydrogenase and malate dehydrogenase during the latter half of pregnancy in the mouse.
The specific activity of 17 beta-hydroxysteroid oxidoreductase (17-HOR) with estradiol-17 beta (E2), estrone (E1) and testosterone (T), as well as that of lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) were measured in homogenates of CF-1 mouse placenta during the latter half of pregnancy. 17-HOR activity with E2 and T increased over 100-fold between days 9 and 12, and 3- to 4-fold between days 15 and 19, with no further change to day 21. In contrast, activity with E1 increased 39-fold between days 9 and 12, 3.8-fold between days 15 and 19 but then decreased between days 19 and 21. The E2/T activity ratio was constant while the E2/E1 ratio increased between days 9 and 21. LDH increased 2-fold between days 9 and 12 with no further increase to day 19. MDH was constant from day 9 to 19. Activity with E2 was inhibited by T, 5 alpha-dihydrotestosterone (5 alpha-DHT) and DHA but not by E1, androstenedione (A) or 20 alpha-dihydroprogesterone. Activity with T was inhibited by E2, 5 alpha-DHT and DHA, but not by A. In contrast, activity with E1 was inhibited by A and DHA but not by E2, T or 5 alpha-DHT. The results suggest placental 17-HOR is developmentally regulated. Although the results are also suggestive of multiple forms of 17-HOR, a single enzyme with an ordered kinetic mechanism cannot be ruled out.
Blomquist
C H
CH
Department of Obstetrics and Gynecology, Ramsey Clinic, St Paul, MN 55101.
Hensleigh
H C
HC
Block
D L
DL
Feeney
L A
LA
D015067:17-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000818:Animals; D003600:Cytosol / Q000201:enzymology; D004958:Estradiol / Q000378:metabolism; D004970:Estrone / Q000378:metabolism; D005260:Female; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008291:Malate Dehydrogenase / Q000378:metabolism*; D051379:Mice; D008861:Microsomes / Q000201:enzymology; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism
D004970:Estrone; D013739:Testosterone; D004958:Estradiol; D015067:17-Hydroxysteroid Dehydrogenases; D007770:L-Lactate Dehydrogenase; D008291:Malate Dehydrogenase