Evidence for urea-induced hypometabolism in isolated organs of dormant ectotherms

Autor: Timothy J. Muir, Jon P. Costanzo, Richard E. Lee
Rok vydání: 2010
Předmět:
Zdroj: Journal of Experimental Zoology Part A: Ecological Genetics and Physiology. :28-34
ISSN: 1932-5231
1932-5223
DOI: 10.1002/jez.572
Popis: Many organisms endure extended periods of dormancy by depressing their metabolism, which effectively prolongs the use of their endogenous energy stores. Though the mechanisms of hypometabolism are varied and incompletely understood, recent work suggests that urea accumulation in autumn and early winter contributes to reduced metabolism of hibernating wood frogs (Rana sylvatica). Urea accumulation during dormancy is a widespread phenomenon, and it has long been presumed that numerous species from diverse taxa benefit from its hypometabolic effect. To investigate the phylogenetic prevalence of urea-induced hypometabolism, we studied four species of urea accumulators from the clades Amphibia (Spea bombifrons and Ambystoma tigrinum), Reptilia (Malaclemys terrapin), and Gastropoda (Anguispira alternata), and one amphibian species (R. pipiens) that does not accumulate urea during dormancy. We measured rates of oxygen consumption (VO2) of excised organ samples from dormant animals in the presence or absence of physiological concentrations of urea. Three of the four urea-accumulating species had at least one organ whose VO2 was significantly decreased by urea treatment. However, VO2 of organs from R. pipiens, the one species tested that does not accumulate urea during dormancy, was not affected by urea treatment. Our results support the hypothesis that urea accumulation can reduce metabolic rate of dormant animals and provide a base for further investigation into the evolution of urea-induced hypometabolism. J. Exp. Zool. 313A:28–34, 2010. © 2009 Wiley-Liss, Inc.
Databáze: OpenAIRE
Externí odkaz: