title: Expression of ovarian 20alpha-hydroxysteroid dehydrogenase in rat thymus.
abstract: Ovarian 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD), which converts progesterone to a derivative devoid of biological activity, plays a crucial role in achieving the short estrous cycle in rats. Although 20alpha-HSD activity has also been demonstrated in the thymus, its molecular nature, function, and regulation of expression have yet to be determined. In the present study we investigated if 20alpha-HSD activity in the thymus originates in a transcript identical to that expressed in the ovary. RT-PCR analysis indicated the expression of 20alpha-HSD mRNA in rat thymus, and sequencing of the PCR product showed 100% identity to ovarian 20alpha-HSD cDNA. Immunohistochemical study using anti-rat ovarian 20alpha-HSD antibody demonstrated the expression of 20alpha-HSD protein in the thymus. The 20alpha-HSD-expressing cells in the thymus seemed to be some type of lymphocyte by their morphology. These results suggest that the same molecular species as ovarian 20a-HSD is expressed in thymic lymphocytes. Therefore, 20alpha-HSD may play a role in T-lymphocyte proliferation and differentiation processes.
authors.affiliation: Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hirabayashi
authors.forename: M
authors.initials: M
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Nishihara
mesh_terms: D015089:20-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D000818:Animals; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D007150:Immunohistochemistry; D010053:Ovary / Q000201:enzymology; D012313:RNA / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D013950:Thymus Gland / Q000201:enzymology*
chemical_list: D012313:RNA; D015089:20-Hydroxysteroid Dehydrogenases; C115140:3 alpha-beta, 20 beta-hydroxysteroid dehydrogenase