title: Effect of age on bone mineral density and the serum concentration of endogenous nitric oxide synthase inhibitors in rats.
abstract: Results of previous studies have indicated that bone mineral density (BMD) is decreased in aged animals and elderly humans, and that treatment with nitric oxide (NO) donors prevents bone loss. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, can inhibit NO synthesis. In the study reported here, we examined age-related changes in the serum content of ADMA and in BMD in various skeletal regions. The BMD in the lumbar part of the spine, the femur, and the tibia in 12-month-old rats was markedly increased, compared with that in 6-month-old rats, and the BMD in 20-month-old rats was decreased, compared with that in 12-month-old rats. Serum concentration of ADMA in 20-month-old rats was significantly increased, compared with that in 6- or 12-month-old rats. A similar age-related change in the concentration of lipid peroxide also was seen in the three age groups. These results suggest that the increased amount of endogenous ADMA may be associated with an age-related decrease in BMD in rats.
authors.affiliation: Department of Pharmacology, Xiang-Ya School of Medicine, Central South University, Changsha, Hunan, People's Republic of China.
authors.forename: Rong
authors.initials: R
authors.lastname: Lu
authors.forename: Chang-Ping
authors.initials: CP
authors.lastname: Hu
authors.forename: Xian-Ping
authors.initials: XP
authors.lastname: Wu
authors.forename: Er-Yuan
authors.initials: EY
authors.lastname: Liao
authors.forename: Yuan-Jian
authors.initials: YJ
authors.lastname: Li
mesh_terms: D015502:Absorptiometry, Photon; D000375:Aging / Q000502:physiology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood*; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000097:blood*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004791:Enzyme Inhibitors; D008315:Malondialdehyde; C018524:N,N-dimethylarginine; D001120:Arginine; D019001:Nitric Oxide Synthase