title: Expression of activities of two 20 alpha-hydroxysteroid dehydrogenase isozymes in rat corpora lutea.
abstract: The rat ovary contains two isozymes of 20 alpha-hydroxysteroid dehydrogenase (HSD-1 and HSD-2). In this study, the expression of activity of each isozyme was investigated in ovaries that contained a single generation of corpora lutea during pseudopregnancy. This condition was induced by cervical stimulation in rats that had been rendered anovulatory by housing them in a continuously lit environment. The total activity of cytosolic 20 alpha-HSD was lower in the ovaries of these pseudopregnant rats than in ovaries containing multiple generations of corpora lutea. In normal pseudopregnancy, HSD-1 activity was low on days 5 and 9 and increased markedly on day 15, whereas HSD-2 was lower than HSD-1 and did not vary throughout pseudopregnancy. However, on days 5 and 9 of continuous-light pseudopregnancy, low activity of HSD-1 only was detected; by day 15, HSD-1 activity had increased sixfold and HSD-2 activity could be detected. Immunohistochemical methods using a specific antibody recognizing both HSD-1 and HSD-2 revealed that the number of 20 alpha-HSD-positive luteal cells increased by day 15. Thus, the increase in total enzyme activity and appearance of HSD-2 activity observed at late pseudopregnancy was accompanied by an increase in the number of 20 alpha-HSD-positive luteal cells.
authors.affiliation: Department of Veterinary Physiology, University of Tokyo, Japan.
authors.forename: H H
authors.initials: HH
authors.lastname: Seong
authors.forename: K
authors.initials: K
authors.lastname: Shiota
authors.forename: K
authors.initials: K
authors.lastname: Noda
authors.forename: A
authors.initials: A
authors.lastname: Ogura
authors.forename: T
authors.initials: T
authors.lastname: Asano
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D015089:20-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis* / Q000302:isolation & purification; D043607:20-alpha-Hydroxysteroid Dehydrogenase; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003338:Corpus Luteum / Q000201:enzymology*; D003600:Cytosol / Q000201:enzymology; D004971:Estrus / Q000378:metabolism; D005260:Female; D005455:Fluorescent Antibody Technique; D007527:Isoenzymes / Q000096:biosynthesis*; D051379:Mice; D008813:Mice, Inbred ICR; D010053:Ovary / Q000201:enzymology / Q000648:ultrastructure; D011555:Pseudopregnancy / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
chemical_list: D007527:Isoenzymes; D015089:20-Hydroxysteroid Dehydrogenases; D043607:20-alpha-Hydroxysteroid Dehydrogenase