Chinchilla laniger - discrepancy between concentrating ability and kidney structure

A discrepancy between the concentrating ability and kidney structure was found in the rodent, Chinchilla laniger. Maximal urine concentration under water deprivation or in response to administration of antidiuretic hormone, was lower in the chinchilla than in the albino rat while the papilla of the chinchilla is considerably longer and comparable to the papillas of rodents with the highest concentrating ability (Jerboa and Kangaroo rat). No reduction of urinary sodium concentration under food deprivation was observed in the chinchilla. The possibility of altered sensitivity to antidiuretic hormone and/or mineralocorticoids is discussed.