Exercise-induced catabolic responses in various muscle fibres.
In Wistar rats a 10-hr swim caused an immediate increase of 3-methylhistidine and free tyrosine content in the white portion of quadriceps muscle. In the red portion the elevated levels of these amino acids were observed within 6 to 48 hrs of postexercise recovery. The glycogen depletion was substantially higher in the red portion of the muscle, indicating that the most active were oxidative-glycolytic fibres during the exercise. In conclusion, during exercise the most active muscle fibres do not contribute to the mobilization of protein resources. In a later part of postexercise recovery, catabolic changes occur in most active fibres, constituting, reasonably, a part of enhanced protein turnover.
Varrik
E
E
Laboratory of Hormonal Regulation of Muscular Activity, Tartu University, Ylikooli, Estonia.
Viru
A
A
Oöpik
V
V
Viru
M
M
D000818:Animals; D006003:Glycogen / Q000032:analysis; D008112:Liver Glycogen / Q000032:analysis; D008762:Methylhistidines / Q000032:analysis; D009124:Muscle Proteins / Q000032:analysis; D009132:Muscles / Q000737:chemistry / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013550:Swimming
D008112:Liver Glycogen; D008762:Methylhistidines; D009124:Muscle Proteins; D006003:Glycogen; C028118:3-methylhistidine