QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online July 23, 2003

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bozinovic, F. Articles by Cortés, A. Search for Related Content PubMed PubMed Citation Articles by Bozinovic, F. Articles by Cortés, A. Social Bookmarking                         What's this?

The Journal of Experimental Biology 206, 2959-2966 (2003)
doi: 10.1242/jeb.00509

Seasonal acclimatization in water flux rate, urine osmolality and kidney water channels in free-living degus: molecular mechanisms, physiological processes and ecological implications

Francisco Bozinovic^1,*, Pedro A. Gallardo², G. Henk Visser^3,4 and Arturo Cortés⁵

¹ Center for Advanced Studies in Ecology & Biodiversity and Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile, 6513677
² Laboratorio de Fisiopatología Molecular, Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile, 6513677
³ Centre for Isotope Research, Nijenborgh 4, 9747 AG Groningen, The Netherlands
⁴ Zoological Laboratory, PO Box 14, 9750 AA Haren, The Netherlands
⁵ Departamento de Biología, Facultad de Ciencias Universidad de La Serena, Casilla 599, La Serena Chile

^* Author for correspondence (e-mail: fbozinov{at}genes.bio.puc.cl)

Accepted 20 May 2003

The environmental modification of an organism's physiology in the field is often hypothesized to be responsible for allowing an organism to adjust to changing biotic and abiotic environmental conditions through increases in biological performance. Here, we examine the phenotypic flexibility of water flux rate, urine osmolality and the expression of kidney aquaporins (AQP; or water channels) in free-ranging Octodon degus, a South American desert-dwelling rodent, through an integrative study at cellular, systemic and organismal levels. Water flux rates varied seasonally and were significantly lower in austral summer than in winter, while urine osmolality was higher in summer than during winter. The observed water influx rate during summer was 10.3±2.3 ml day^-1 and during winter was 40.4±9.1 ml day^-1. Mean urine osmolality was 3137±472 mosmol kg^-1 during summer and 1123±472 mosmol kg^-1 during winter. AQP-2 medullary immunolabeling was more abundant in the kidneys of degus captured during summer than those captured during winter. This immunoreactivity was higher in apical cell membranes of medullary collecting ducts of degus in summer. AQP-1 immunostaining did not differ between seasons. Consistently, AQP-2 protein levels were increased in medulla from the summer individuals, as judged by the size of the 29 kDa band in the immunoblot. Here, we reveal how the integration of flexible mechanisms acting at cellular, systemic and organismal levels allows a small desert-dwelling mammal to cope with seasonal water scarcity in its semi-arid habitat.

Key words: acclimatization, arid environment, water economy, rodent, aquaporin, degu, Octodon degus

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				R. V. Floyd, S. L. Mason, C. J. Proudman, A. J. German, D. Marples, and A. Mobasheri Expression and nephron segment-specific distribution of major renal aquaporins (AQP1-4) in Equus caballus, the domestic horse Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2007; 293(1): R492 - R503. [Abstract] [Full Text] [PDF]