title: Immunoreactivities and levels of mineralocorticoid and glucocorticoid receptors in the hippocampal CA1 region and dentate gyrus of adult and aged dogs.
abstract: Corticosteroids are important factors in the maintenance of homeostasis in the brain. They are regulated via the interaction with two corticosteroid receptor systems-the mineralocorticoid (MR) and glucocorticoid receptor (GR). In the present study, we observed age-related changes in serum cortisol levels, and immunoreactivities and protein levels of MR and GR in the hippocampal CA1 region and dentate gyrus. The serum cortisol levels were significantly high (about twofold) in the aged group compared to that in the adult group. In the adult dog (2-3 years old), MR and GR immunoreactivity was detected in neurons in the pyramidal layer of the CA1 region, and in the granular and multiform layers of the dentate gyrus. In the aged dog (10-12 years old), MR immunoreactivity in the CA1 region was significantly decreased, especially, in the dentate multiform layer. In contrast, GR immunoreactivity in the aged dog was slightly decreased in the CA1 region and dentate gyrus. In the Western blot analysis, MR protein level in the aged dog was significantly lower compared to that of the adult dog; GR protein level in the aged dog was not significantly decreased. This result indicates that the reduction of MR immunoreactivity and protein level in the hippocampus of the aged dog may be associated with neural dysfunction in the aged hippocampus.
authors.affiliation: Department of Anatomy and Cell Biology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, South Korea.
authors.forename: Jung Hoon
authors.initials: JH
authors.lastname: Choi
authors.forename: In Koo
authors.initials: IK
authors.lastname: Hwang
authors.forename: Choong Hyun
authors.initials: CH
authors.lastname: Lee
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Chung
authors.forename: Ki-Yeon
authors.initials: KY
authors.lastname: Yoo
authors.forename: Hua
authors.initials: H
authors.lastname: Li
authors.forename: Moo-Ho
authors.initials: MH
authors.lastname: Won
authors.forename: Je Kyung
authors.initials: JK
authors.lastname: Seong
authors.forename: Yeo Sung
authors.initials: YS
authors.lastname: Yoon
authors.forename: In Se
authors.initials: IS
authors.lastname: Lee
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D018891:Dentate Gyrus / Q000254:growth & development / Q000378:metabolism*; D004285:Dogs; D006624:Hippocampus / Q000254:growth & development / Q000378:metabolism*; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D011965:Receptors, Glucocorticoid / Q000096:biosynthesis*; D018161:Receptors, Mineralocorticoid / Q000096:biosynthesis*
chemical_list: D011965:Receptors, Glucocorticoid; D018161:Receptors, Mineralocorticoid; D006854:Hydrocortisone