Seasonal effects of hyper‐osmotic sodium chloride on urea production in the frog, Rana pipiens

Publisher Website
Google Scholar
Abstract
Spring‐summer frogs, Rana pipiens, acclimated at 22.5°C or 27°C were dehydrated in 0.15 M NaCl for up to 24 hours. After 10 or 24 hours of treatment, the concentration of urea in serum increases relative to the concentrations of urea measured in serum of frogs kept in tap water or 0.125 M NaCl. The increase in the concentration of urea in serum of spring‐summer frogs was associated with an increase in body urea and an increased rate of urea production. When fall‐winter frogs, acclimated at 20°C, were dehydrated in 0.15 M NaCl for 12.5 hours, no increase in the concentration of urea in serum was observed, relative to frogs treated with tap water or 0.125 M NaCl. After 48 hours, the concentration of urea in serum of frogs treated with 0.15 M or 0.125 M NaCl was the same, but both were significantly greater than tap water treated frogs. The metabolic basis for the increase in the rate of urea production observed in spring‐summer but not fall‐winter frogs in response to hyperosmotic sodium chloride is discussed.