title: The role of myostatin and the calcineurin-signalling pathway in regulating muscle mass in response to exercise training in the rainbow trout Oncorhynchus mykiss Walbaum.
abstract: Rainbow trout Oncorhynchus mykiss Walbaum were exercised at 0.8 and 1.6 body lengths s(-1) for 18 h a day over a 30 day period. Exercise resulted in a 24-30% increase in the average cross-sectional area of fast muscle fibres relative to tank-rested controls. The concentrations of growth factors and transcription factors hypothesised to play a role in regulating exercise-induced muscle fibre hypertrophy were measured. Exercise training resulted in a minor increase in calcineurin localisation in the nucleus. However, nuclear factor of T-cells 2 (NFAT2) nuclear localisation did not follow a pattern that was consistent with NFAT2-mediated transcriptional activity and changes in calcineurin signaling. The active peptide of myostatin, a negative regulator of muscle growth in mammals, was downregulated in exercise groups relative to tank-rested controls, but only by 6-7%. It was concluded that myostatin and calcineurin signaling do not play a major role in regulating exercise-induced muscle hypertrophy in trout.
authors.affiliation: Gatty Marine Laboratory, School of Biology, University of St Andrews, St Andrews, Scotland KY16 8LB, UK.
authors.forename: C I
authors.initials: CI
authors.lastname: Martin
authors.forename: I A
authors.initials: IA
authors.lastname: Johnston
mesh_terms: D000818:Animals; D019703:Calcineurin / Q000378:metabolism / Q000502:physiology*; D015870:Gene Expression; D051379:Mice; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology; D018482:Muscle, Skeletal / Q000254:growth & development* / Q000378:metabolism; D055435:Myostatin; D017686:Oncorhynchus mykiss / Q000378:metabolism / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D020317:Salmo salar; D015398:Signal Transduction / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000502:physiology*
chemical_list: C525912:Mstn protein, mouse; C525913:Mstn protein, rat; D055435:Myostatin; D016212:Transforming Growth Factor beta; D019703:Calcineurin