title: Age-related changes in metabolic properties of equine skeletal muscle associated with muscle plasticity.
abstract: The purpose of the present study was to determine the age-related changes in myosin heavy chain (MHC) composition and muscle oxidative and glycolytic capacity in 18 horses ranging in age from two to 30 years. Muscle samples were collected by excisional biopsy of the semimebranosus muscle. MHC expression and the key enzymatic activities were measured. There was no significant correlation between horse age and the proportions of type-IIA and type-IIX MHC isoforms. The percentage of type-I MHC isoforms decreased with advancing age. Muscle citrate synthase activity decreased, whereas lactate dehydrogenase activity increased with increasing age. Muscle 3-OH acyl CoA dehydrogenase activity did not change with ageing. The results suggest that, similar to humans, the oxidative capacity of equine skeletal muscle decreases with age. The age-related changes in muscle metabolic properties appear to be consistent with an age-related transition in MHC isoforms of equine skeletal muscle that shifts toward more glycolytic isoforms with age.
authors.affiliation: Section of Sport and Exercise Sciences, The Ohio State University, Columbus, OH 43210-1284, USA.
authors.forename: Jeong-su
authors.initials: JS
authors.lastname: Kim
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Hinchcliff
authors.forename: Mamoru
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Beard
authors.forename: Chad D
authors.initials: CD
authors.lastname: Markert
authors.forename: Steven T
authors.initials: ST
authors.lastname: Devor
mesh_terms: D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D000375:Aging; D000818:Animals; D002950:Citrate (si)-Synthase / Q000378:metabolism; D005260:Female; D006736:Horses / Q000254:growth & development*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000254:growth & development* / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000378:metabolism*
chemical_list: D015094:3-Hydroxyacyl CoA Dehydrogenases; D007770:L-Lactate Dehydrogenase; D002950:Citrate (si)-Synthase; D018995:Myosin Heavy Chains