Morphological traits and molecules involved in the renal concentrating ability of South American hystricognath rodents

DIAZ, G. B., R. A. OJEDA, S. BRENGIO, M. DACAR, J. SARMIENTO, G. KAUSEL; M. H. GALLARDO

Florida Atlantic University, Boca Raton, Florida USA

Congreso; 7th International Congress of Vertebrate Morphology; 2004

Morphological traits and molecules involved in the renal concentrating ability of South American hystricognath rodents Morphological traits and molecules involved in the renal concentrating ability of South American hystricognath rodents Instituto de Ecología y Evolución, Universidad Austral de Chile, Arid environments represent a challenge for animals to maintain water balance. One way to conserve body water in mammals is to excrete concentrated urine. Different renal indices based on the development of the renal medulla are typical estimates of urine concentration. But it is also determined by the arrangement of vascular bundles and development of pelvic extensions as well as the expression of some molecules such as the antidiuretic hormone receptor and water channels. In this study we assess all these renal features (including organ, tissue and molecular levels) in hystricognath rodent species of South America due to their wide range of ecological adaptations to aridity. Stemming from phylogenetic analyses, it appears that the adaptive response of the different renal traits to osmoregulation has evolved independently. The tetraploid octodontids specialized in halophytic chenopods posses most of the renal traits associated with an increased urine-concentrating ability. The comprehensive approach used in this study and the particular cases reported here may contribute to understand the kind and degree of osmoregulatory strategies in rodents.>Partially funded by FNC 1010727, CONICET and Fundación Antorchas.