title: Glucocorticoid metabolism in the bovine cumulus-oocyte complex matured in vitro.
abstract: Glucocorticoid action in target organs is regulated by relative activities of 11β-HSD type 1 (HSD11B1) that mainly converts cortisone to active cortisol and type 2 (HSD11B2) that inactivates cortisol to cortisone. HSD11Bs have been shown to be expressed in the ovary of various species. However, little is known about the expression and activity of HSD11Bs in the bovine cumulus-oocyte complex (COC). In the present study, we investigated the expression and activities of HSD11Bs in in vitro-matured (IVM) bovine COCs. Bovine COCs were matured in M199 supplemented with or without FSH and FCS. The expression of HSD11B1 and HSD11B2 was measured by using quantitative RT-PCR in denuded oocytes (DO) and cumulus cells (CC). Reductive and oxidative activities of HSD11Bs were determined by radiometric conversion assay using labeled cortisol, cortisone or dexamethasone in intact COCs, DO or CC in the presence or absence of 11-keto-progesterone (11kP), a selective inhibitor of HSD11B2. The presence of HSD11Bs in the oocyte was examined by immunofluorescence microscopy. Oocytes exclusively expressed HSD11B2 and its expression and activity were largely unchanged during IVM. CC, on the other hand, exclusively expressed HSD11B1 and its expression and activity were upregulated as IVM progressed. As a result, the net glucocorticoid metabolism shifted from inactivation to activation towards the end of IVM. These results indicate that the bovine COC is capable of modulating local glucocorticoid concentration and, by doing so, may create an environment that is favorable to ovulating oocyte for maturation, fertilization and subsequent development.
authors.affiliation: Department of Life Science and AgricultureObihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan mtetsuka@obihiro.ac.jp.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Tetsuka
authors.affiliation: Department of Life Science and AgricultureObihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Takagi
authors.affiliation: Department of Life Science and AgricultureObihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Ambo
authors.affiliation: Department of Life Science and AgricultureObihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Thet Su
authors.initials: TS
authors.lastname: Myat
authors.affiliation: Department of Life Science and AgricultureObihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Zempo
authors.affiliation: Department of Life Science and AgricultureObihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Asuka
authors.initials: A
authors.lastname: Onuma
mesh_terms: D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1 / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2 / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D003348:Cortisone / Q000378:metabolism; D054885:Cumulus Cells / Q000201:enzymology / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D005938:Glucocorticoids / Q000378:metabolism*; D006854:Hydrocortisone / Q000378:metabolism; D059471:In Vitro Oocyte Maturation Techniques / Q000662:veterinary*; D009865:Oocytes / Q000201:enzymology / Q000378:metabolism*; D010084:Oxidation-Reduction; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D005938:Glucocorticoids; D043205:11-beta-Hydroxysteroid Dehydrogenase Type 1; D043209:11-beta-Hydroxysteroid Dehydrogenase Type 2; D003348:Cortisone; D006854:Hydrocortisone