Journal of Applied Physiology, Vol 42, Issue 2 295-299, Copyright © 1977 by American Physiological Society
Effects of cold exposure and dehydration on renal function in black-tailed prairie dogs
J. D. Hamilton and E. W. Pfeiffer
Black-tailed prairie dogs (Cynomys ludovicianus) were deprived of food and
water for several weeks during the fall and winter in a cold-room
hibernaculum (Ta 5-8 degrees C), and for several days at room temperature
during the summer. Body temperatures (Tb) were determined periodically in
nine animals by radiotransmitters implanted in the abdomen. Animals
deprived of food and water in the summer were killed when maximum urine
concentration was achieved. Eight animals in the winter were active when
killed after 7-35 days in the hibernaculum with Tb between 18 and 36
degrees C. Five animals that became torpid periodically in the winter were
killed after 19-42 days in the hibernaculum when their Tb indicated torpor
(Tb less than 13 degrees C). Active animals in the summer and winter
possessed pronounced renal corticomedullary urea and sodium concentration
gradients. Torpid animals lacked these gradients and had lower urine and
plasma osmotic concentrations than active animals. Plasma urea values and
terminal osmolal U/P ratios were lowest in torpid prairie dogs.
