Biochemical data on some organs from normal or prolactin-treated Xenopus laevis (Daudin) adults reared in fresh and in salt water

The effects of salinity and of prolactin treatment on urea synthesis in the liver, and on the shift from ammonotelic to ureotelic excretion, were studied in adult Xenopus laevis. The activity of both arginase and urea synthesis in the liver increased in the animals reared in salt water. This rise is reduced by prolactin treatment. In addition, estimation of the activity of alkaline phosphomonoesterase (taken as a test of the functional condition of the adrenal glands) showed that it decreases in salt water animals. This decrease was more pronounced after prolactin treatment. Increase in the level of sodium in the muscle tissue, which is connected with the level of this ion in the blood, occurred in the salt water animals and was further enhanced by prolactin treatment.