Renal function in amphibians: A comparison of strictly aquatic and amphibious species, with observations on the effects of anesthesia

Abstract

1. 1. Renal clearance measurements were used to compare urine flow ( V), glomerular filtration rate (GFR), and renal tubular solute transport properties in strictly aquatic and amphibious amphibians. 2. 2. Aquatic Necturus maculosus and Cryptobranchus alleganiensis have generally lower V, GFR, and higher fractional electrolyte reabsorption than the amphibious Taricha granulosa. Fractional water reabsorption was lower in N. maculosus than in T. granulosa but it was highest of all in C. alleganiensis. 3. 3. Tricaine methanesulfonate anesthesia lowers V, GFR, and elevates fractional water reabsorption in N. maculosus. 4. 4. Neither N. maculosus nor T. granulosa secrete urea; both reabsorb this product in direct proportion to water. 5. 5. The results are discussed in the context of renal parameters published for other amphibian species.