title: Influence of flight on protein catabolism, especially myofilament breakdown, in homing pigeons.
abstract: In order to study protein degradation during flight in homing, a high-performance liquid chromatography technique was developed for the quantitative analysis of N tau-methylhistidine. Secondly, it was necessary to confirm that the excretion of N tau-methylhistidine correlates with myofilament breakdown in homing pigeons. In these experiments, ten birds were subcutaneously injected with N tau-[14C]methylhistidine and the excreta were quantitatively collected for 1 week. Of the 94.5% radioactivity recovered, 87.1% was associated with N tau-[14C]methylhistidine and 6.1% with N-acetyl-N tau-[14C]methylhistidine. This rapid excretion of unmetabolized N tau-[14C]methylhistidine validates the assumption that the amount of N tau-methylhistidine excreted is a measure of myofilament catabolism in homing pigeons. The influence of endurance flight on protein breakdown was determined after flights from release sites 368-646 km away. Immediately after return, plasma urea and uric acid levels were increased, whereas plasma concentration of N tau-methylhistidine remained unchanged compared to unflown control birds. Flown pigeons excreted significantly more urea and N tau-methylhistidine within 24 h and significantly more urea and uric acid within 96 h after flight than unflown controls. Our findings support the hypothesis that in homing pigeons protein catabolism is increased during endurance flight. Elevated N tau-methylhistidine excretion probably results from repair processes in damaged muscle fibers, including breakdown of myofilaments.
authors.affiliation: Institut für Haustierkunde, Christian-Albrechts-Universität, Kiel, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Bordel
authors.forename: E
authors.initials: E
authors.lastname: Haase
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D000818:Animals; D002250:Carbon Radioisotopes; D010856:Columbidae / Q000097:blood / Q000502:physiology*; D005243:Feces / Q000737:chemistry; D005426:Flight, Animal / Q000502:physiology*; D008762:Methylhistidines / Q000097:blood; D009124:Muscle Proteins / Q000378:metabolism*; D014508:Urea / Q000097:blood; D014527:Uric Acid / Q000097:blood
chemical_list: D002250:Carbon Radioisotopes; D008762:Methylhistidines; D009124:Muscle Proteins; D014527:Uric Acid; D014508:Urea; C028118:3-methylhistidine