Seasonal dynamics of flight muscle fatty acid binding protein and catabolic enzymes in a migratory shorebird.
We developed an ELISA to measure heart-type fatty acid binding protein (H-FABP) in muscles of the western sandpiper (Calidris mauri), a long-distance migrant shorebird. H-FABP accounted for almost 11% of cytosolic protein in the heart. Pectoralis H-FABP levels were highest during migration (10%) and declined to 6% in tropically wintering female sandpipers. Premigratory birds increased body fat, but not pectoralis H-FABP, indicating that endurance flight training may be required to stimulate H-FABP expression. Juveniles making their first migration had lower pectoralis H-FABP than adults, further supporting a role for flight training. Aerobic capacity, measured by citrate synthase activity, and fatty acid oxidation capacity, measured by 3-hydroxyacyl-CoA-dehydrogenase and carnitine palmitoyl transferase activities, did not change during premigration but increased during migration by 6, 12, and 13%, respectively. The greater relative induction of H-FABP (+70%) with migration than of catabolic enzymes suggests that elevated H-FABP is related to the enhancement of uptake of fatty acids from the circulation. Citrate synthase, 3-hydroxyacyl-CoA-dehydrogenase, and carnitine palmitoyl transferase were positively correlated within individuals, suggesting coexpression, but enzyme activities were unrelated to H-FABP levels.
Guglielmo
Christopher G
CG
Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6. cgugliel@selway.umt.edu
Haunerland
Norbert H
NH
Hochachka
Peter W
PW
Williams
Tony D
TD
D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000378:metabolism; D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D001717:Birds / Q000502:physiology*; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004798:Enzymes / Q000378:metabolism*; D050556:Fatty Acid-Binding Proteins; D005260:Female; D005426:Flight, Animal / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D009363:Neoplasm Proteins; D010807:Physical Endurance / Q000502:physiology; D012621:Seasons; D012727:Sex Characteristics
D002352:Carrier Proteins; D004798:Enzymes; D050556:Fatty Acid-Binding Proteins; D009363:Neoplasm Proteins; D015094:3-Hydroxyacyl CoA Dehydrogenases; D002334:Carnitine O-Palmitoyltransferase; D002950:Citrate (si)-Synthase