Journal of Applied Physiology, Vol 47, Issue 5 923-926, Copyright © 1979 by American Physiological Society
Effect of Sindbis birus infection on survival of mice in the cold
R. N. Moore, G. M. Shackleford, R. F. Garry and L. J. Berry
Mice infected with 10(9) plaque-forming units (PFU) of Sindbis virus 9 h
prior to exposure to cold (5 degrees C) died more rapidly after entering
the new environment than saline-injected control mice. The early deaths
occurred in animals singly housed without bedding and only when food was
withheld. Because deaths could be prevented by providing the infected
animals with food, it was concluded that metabolic alteractions resulting
from the virus infection were responsible for the deaths. As evidence,
corticosteroid-inducible hepatic enzymes did not respond to hydrocortisone
administration in virus-infected mice housed at 5 degrees C.
Phosphoenolpyruvate carboxykinase (PEPCK) (EC 4.1.1.32) was induced
significantly in control mice held at 5 degrees C for 5 h, but failed to
induce in infected mice in the cold. Tryptophan oxygenase (TO) (EC
1.13.11.11) activity was also induced in control mice at 5 degrees C, but
was too low to be measured in livers of all infected mice including those
exposed to cold. The conclusion that Sindbis virus-infected mice were
unable to make the metabolic adjustments required for survival at 5 degrees
C was further indicated by severe hypoglycemia and rapid drop in rectal
temperature that occurred in infected mice after 5 h in the cold.
