title: Assessment of protein synthesis in highly aerobic canine species at the onset and during exercise training.
abstract: Canis lupus familiaris, the domesticated dog, is capable of extreme endurance performance. The ability to perform sustained aerobic exercise is dependent on a well-developed mitochondrial reticulum. In this study we examined the cumulative muscle protein and DNA synthesis in groups of athletic dogs at the onset of an exercise training program and following a strenuous exercise training program. We hypothesized that both at the onset and during an exercise training program there would be greater mitochondrial protein synthesis rates compared with sedentary control with no difference in mixed or cytoplasmic protein synthesis rates. Protein synthetic rates of three protein fractions and DNA synthesis were determined over 1 wk using (2)H2O in competitive Alaskan Huskies and Labrador Retrievers trained for explosive device detection. Both groups of dogs had very high rates of skeletal muscle protein synthesis in the sedentary state [Alaskan Huskies: Mixed = 2.28 ± 0.12, cytoplasmic (Cyto) = 2.91 ± 0.10, and mitochondrial (Mito) = 2.62 ± 0.07; Labrador Retrievers: Mixed = 3.88 ± 0.37, Cyto = 3.85 ± 0.06, and Mito = 2.92 ± 0.20%/day]. Mitochondrial (Mito) protein synthesis rates did not increase at the onset of an exercise training program. Exercise-trained dogs maintained Mito protein synthesis during exercise training when mixed (Mixed) and cytosolic (Cyto) fractions decreased, and this coincided with a decrease in p-RpS6 but also a decrease in p-ACC signaling. Contrary to our hypothesis, canines did not have large increases in mitochondrial protein synthesis at the onset or during an exercise training program. However, dogs have a high rate of protein synthesis compared with humans that perhaps does not necessitate an extra increase in protein synthesis at the onset of aerobic exercise training.
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado; benjamin.f.miller@colostate.edu.
authors.forename: Benjamin F
authors.initials: BF
authors.lastname: Miller
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Ehrlicher
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Joshua C
authors.initials: JC
authors.lastname: Drake
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Frederick F
authors.initials: FF
authors.lastname: Peelor
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Laurie M
authors.initials: LM
authors.lastname: Biela
authors.affiliation: Department of Animal Science, North Carolina State University, Raleigh, North Carolina; and.
authors.forename: Shannon
authors.initials: S
authors.lastname: Pratt-Phillips
authors.affiliation: Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma.
authors.forename: Michael
authors.initials: M
authors.lastname: Davis
authors.affiliation: Department of Health and Exercise Science, Colorado State University, Fort Collins, Colorado;
authors.forename: Karyn L
authors.initials: KL
authors.lastname: Hamilton
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000332:Aerobiosis / Q000502:physiology; D000818:Animals; D004247:DNA / Q000096:biosynthesis*; D004285:Dogs / Q000145:classification / Q000502:physiology*; D005260:Female; D008297:Male; D008931:Mitochondria, Muscle / Q000502:physiology; D024101:Mitochondrial Proteins / Q000096:biosynthesis; D009124:Muscle Proteins / Q000096:biosynthesis*; D018482:Muscle, Skeletal / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000379:methods*; D010807:Physical Endurance / Q000502:physiology*; D013045:Species Specificity
chemical_list: D024101:Mitochondrial Proteins; D009124:Muscle Proteins; D004247:DNA
keywords: comparative; deuterium oxide; dogs; exercise; stable isotope