Factors Influencing the Secretion of Nitrogen in Sheep Saliva

SUMMARY Differential responses occurred in the amount of urea nitrogen and total nitrogen secreted in the parotid saliva, according to the nitrogen status of the sheep, when 1·4 gm. of urea nitrogen was injected into the blood daily. Of this amount of nitrogen, 0·1 gm. could be recovered in the secretion from one parotid gland daily when the sheep were in positive nitrogen balance, and 0·3 gm. when the sheep were in negative nitrogen balance. The urinary excretion accounted for 1·0 gm. of the 1·4 gm. of urea nitrogen injected daily when the sheep were in positive nitrogen balance, but only 0·3 gm. per day at the lower nitrogen status. The implications of these findings were discussed in relation to a urea conservation mechanism in sheep.