AJP - Regulatory, Integrative and Comparative Physiology, Vol 238, Issue 1 113-R118, Copyright © 1980 by American Physiological Society
Water balance in the California newt, Taricha torosa
S. C. Brown and P. S. Brown
Both dehydration to 87% of original body weight (Wo) and arginine vasotocin
(AVT: 20 mU/g) elicited rapid weight gains (ca. 9% of Wo in the 1st h) when
terrestrial-phase T. torosa were given access to water. In each case, net
weight gain resulted from increased integumental osmosis and antidiuresis.
Mesotocin (0.001 -- 0.1 micrograms/g) elicited modest but significant
weight gains (ca. 1%/h) caused solely by increased integumental osmosis.
Integumental water uptake from wet moss was 66% that of totally immersed
animals. Water movement from ventral to dorsal body surface occurred along
channels on the skin. Urinary bladder storage capacities in excess of 50%
of Wo were observed. Following AVT administration, bladder water resorption
increased significantly, while glomerular filtration rate dropped to 16% of
control values. The structural and physiological adaptations for water
balance in T. torosa are comparable to those found in some terrestrial
anurans.
