AJP - Regulatory, Integrative and Comparative Physiology, Vol 242, Issue 3 189-R194, Copyright © 1982 by American Physiological Society
Muscle enzyme profile, diet, and flight in South American bats
M. E. Yacoe, J. W. Cummings, P. Myers and G. K. Creighton
Activities of four catabolic enzymes (citrate synthase, hexokinase,
3-hydroxyacyl-CoA dehydrogenase, and phosphorylase) were measured in the
pectoralis muscles of 10 species of South American bats, representing four
families. The pattern of enzyme activities in these tissues suggests that
these muscles differ qualitatively with other mammalian and avian muscles
in two respects. First, the muscles of all 10 bat species were much more
highly oriented toward fat metabolism and away from glucose metabolism than
in any previously measured skeletal muscle. Second, the species were
divided into two major groups with respect to hexokinase activity.
Primarily frugivorous species had hexokinase activities about 2-3 times as
high as insectivorous species. It is suggested that the weight restrictions
of flight limit glycogen storage and thus bias muscle metabolism toward
fat. However, the extent to which pectoralis muscles have the capacity for
glucose oxidation appears to be dependent on the intake of dietary glucose.
