Compartmentalization of type I 17 beta-hydroxysteroid oxidoreductase in the human ovary.
The steroid-metabolizing enzyme, type I 17 beta-hydroxysteroid oxidoreductase (17 beta-HSOR) also called 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) plays a key role in ovarian synthesis of 17 beta-estradiol. This is the only enzyme in the steroid-metabolizing pathway which has not been localized in the human ovary by immunohistochemistry. In this study, using antibody directed against human placental cytosolic 17 beta-HSOR (type I), a single protein band with a relative molecular mass of approximately 34 kDa was demonstrated by Western analysis in both human luteinized granulosa cells and placental tissue. In placental tissue, immunoreactive type I 17 beta-HSOR was demonstrated within the syncytiotrophoblast using immunohistochemistry. In human ovary, immunoreactive type I 17 beta-HSOR was localized exclusively in granulosa cells of developing follicles, ranging from primary follicles with a single layer of cuboidal-shaped granulosa cells, preantral follicles with multiple layers of granulosa cells, and large antral follicles. No immunoreactivity was detected in spindle-shaped granulosa cells of primordial follicles, theca interna, theca externa or surrounding stroma. In the corpus luteum, type I 17 beta-HSOR immunoreactivity was localized solely in granulosa-lutein cells. For comparison, immunoreactive 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) was examined in the same tissues. Both theca interna and granulosa cells of preantral and antral follicles exhibited 3 beta-HSD staining. Primary follicles did not exhibit detectable 3 beta-HSD in either granulosa or theca cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Sawetawan
C
C
Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center at Dallas 75235-9032.
Milewich
L
L
Word
R A
RA
Carr
B R
BR
Rainey
W E
WE
D015067:17-Hydroxysteroid Dehydrogenases / Q000032:analysis*; D015096:3-Hydroxysteroid Dehydrogenases / Q000032:analysis; D015153:Blotting, Western; D003338:Corpus Luteum / Q000201:enzymology; D005260:Female; D006107:Granulosa Cells / Q000201:enzymology; D006801:Humans; D007150:Immunohistochemistry; D006080:Ovarian Follicle / Q000201:enzymology; D010053:Ovary / Q000201:enzymology*; D010920:Placenta / Q000201:enzymology; D013799:Theca Cells / Q000201:enzymology; D014018:Tissue Distribution
D015067:17-Hydroxysteroid Dehydrogenases; D015096:3-Hydroxysteroid Dehydrogenases