Water uptake by the crab-eating frogRana cancrivora, as affected by osmotic gradients and by neurohypophysial hormones

Abstract

1. The rate of water uptake across the skin was investigated in live Rana cancrivora, an euryhaline frog which has been reported to tolerate sea water. When they were exposed to distilled water at 29° C, the rate of water uptake was 8·4 ± 0·4 μl./cm².hr; when bathed in solutions ranging from 30 to 570 m-osmole/l., irrespective of whether the solute was sucrose, urea or NaCl, the rate of fluid uptake during the first day was inversely related to the osmolarity of the solution. No appreciable fluid movement was observed when the bathing solution had an osmolar concentration of 270 m-osmole/l.