Development of metabolic enzyme activity in locomotor and cardiac muscles of the migratory barnacle goose.. Bishop, Charles M., Patrick J. Butler, Stuart Egginton, Alicia J. El Haj, and Geir W. Gabrielsen. School of Biological Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK., 1 Department of Physiology, School of Medicine, Birmingham University., 2 Norwegian Institute for Nature Research, c/o Tromso Museum, University of Tromso, Tromso, Norway.
APStracts 2:0003R, 1995.
Pre-flight development of the goslings was typified by rapid increases in the aerobic enzymes of the semimembranosus and heart ventricular muscles resulting in near adult values by 3 weeks of age. In constrast, aerobic capacity of the pectoralis muscle, initially developed slowly but showed a rapid increase between 5 and 7 weeks of age, in preparation for becoming airborne. Activities of glycolytic enzymes in the pectoralis muscle showed similar patterns of development as those found for the aerobic enzymes, except for hexokinase which was low at all ages, indicating an adaptation for catabolism of both intracellular glycogen and plasma fatty acids in preference to plasma glucose. Muscle mass-specific activity of citrate synthase in the pectoralis increased by only 33% from goslings, during the first few days of flight, compared to pre-migratory geese. Activities of anaerobic glycolytic enzymes in the ventricles were low, but values for hexokinase, which is involved in the phosphorylation of plasma glucose, developed rapidly. Values for lactate dehydrogenase were also high, reflecting the capacity of the heart to catabolise plasma lactate. Substrate flux supplied by carnitine palmitoyltransferase and oxoglutarate dehydrogenase, in the pectoralis muscles of the pre-migratory geese, appear to have the smallest excess capacities to meet the requirements of sustained aerobic flight. The average maximum oxygen uptake, as indicated by values for OGD, for pre-migratory geese during flight is calculated to be 484 ml O2 min -1 (or 208 ml O2 min-1 kg-1). 

Received 2 June 1994; accepted in final form 3 January 1995.
APS Manuscript Number R301-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative Comp.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.