Steroid aromatization by a small particle fraction from porcine ovaries.
Testosterone, 4-androstene-3,17-dione, 19-hydroxy-4-androstene-3,17-dione, 4alpha-5-oxido-5alpha-androstane-3,17-dione and 4beta-5-oxido-5beta-androstane-3,17-dione were compared as substrates for aromatization by the small particle fraction from sow ovaries. Relative conversion rates were: 19-hydroxy-4-androstene-3,17-dione:4-androstene-3,17-dione: testosterone: 4alpha-5-oxido-5alpha- and 4beta-5-oxido-5beta-androstane-3,17-dione; 100:32:20:congruent to O. Apparent Michaelis constants were 4.4 muM for 4-androstene-3,17-dione and 12 muM for testosterone. Maximum velocities were 0.20 pmoles/mg protein per min for androstenedione [1] and 0.16 for testosterone. The substrate preferences of the aromatizing system found in ovary are similar to those of the enzyme found in placenta.
D000728:Androgens / Q000378:metabolism*; D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D001141:Aromatase / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism; D005260:Female; D010053:Ovary / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism*; D013552:Swine; D013739:Testosterone / Q000378:metabolism*
D000728:Androgens; D004852:Epoxy Compounds; D013739:Testosterone; D000735:Androstenedione; D010088:Oxidoreductases; D001141:Aromatase