Pattern and tissue distribution of catechol estrogen forming activity by pig conceptuses during the peri-implantation period.
The profile of catechol estrogen formation by pig conceptuses from d 14 to 20 of pregnancy (d 0 = 1st d of estrus) was studied using a direct product isolation assay for estrogen-2/4-hydroxylase (E-2/4-H). High performance liquid chromatography was coupled to detection of radioactive products in a flowing system to separate the 2- and 4-hydroxyestradiol (2- and 4-OH-E2) formed from estradiol. The major product was 2-OH-E2; its formation increased with increasing amounts of nicotinamide cofactors and exhibited a preference for NADPH. Maximum velocities were 909 and 154 pmol.mg protein-1.30 min-1, and apparent Michaelis constants were 7.14 and 5.12 microns, for 2- and 4-OH-E2 formation, respectively. Homogenates of d-13 conceptuses produced 1,151 +/- 142 pmol.mg protein-1.30 min-1 of 2-OH-E2. Estradiol-2-hydroxylase was affected (P less than .01) by day of pregnancy, and day effects from d 14 to 20 were described by a fourth-order equation (P less than .001). Conceptuses collected on d 14 produced 119 +/- 15.4 pmol of 2-OH-E2.mg protein-1.30 min-1. By d 15, E-2-activity had declined to 15.7 +/- 1.8 pmol.mg protein-1.30 min-1. Formation of 2-OH-E2 increased to 64.2 +/- 15.4 pmol.mg protein-1.30 min-1 on d 17, remained stable through d 19, and was 39.4 +/- 13.8 pmol.mg protein-1. 30 min-1 on d 20. Therefore, E-2/4-H activity appears to be regulated from d 14 to 20 of pregnancy in pigs; it may participate in the establishment of pregnancy.
Chakraborty
C
C
Dept. of Obstet. Gynecol. and Physiol., University of Kansas, Kansas City 66103.
Dey
S K
SK
Davis
D L
DL
D000818:Animals; D001141:Aromatase / Q000378:metabolism*; D001189:Aryl Hydrocarbon Hydroxylases; D001755:Blastocyst / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1; D010064:Embryo Implantation; D004622:Embryo, Mammalian / Q000201:enzymology*; D047108:Embryonic Development; D002393:Estrogens, Catechol / Q000096:biosynthesis*; D005260:Female; D011247:Pregnancy; D013250:Steroid Hydroxylases / Q000378:metabolism*; D013552:Swine / Q000196:embryology*
D002393:Estrogens, Catechol; D013250:Steroid Hydroxylases; D001141:Aromatase; D001189:Aryl Hydrocarbon Hydroxylases; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1; C020120:estrogen 2-hydroxylase