Some Effects of Histamine on the Acid-Base Balance.

Abstract

The “alkaline tide” in the urine during the digestive period is commonly regarded as a compensatory process, eliminating the excess of base left in the blood after the formation of HCl in the stomach. Some of the observed variations in urine reaction, however, may be indirectly dependent on the absorption of food. So far as we are aware the alkaline tide has not been shown to accompany gastric secretion in the fasting subject. Ackman 1 studied the urine reaction in man, giving a test meal followed immediately by the administration of histamine. The food factor was therefore not eliminated. It seems that the use of histamine alone might give more valuable information as to the cause of the tide.

Female dogs, weighing from 9.0 to 12.5 kg., and having fasted for 16 to 20 hours, were used in our experiments. Measurements of pH were made on urine by the potentiometer, and on blood plasma by the method of Hastings and Sendroy. 2 In the studies on urine, each animal was as a rule used for a single experiment of 4 to 6 hours, in order to avoid the effects of a possible cystitis from the use of the catheter. Histamine dichloride was injected subcutaneously, the usual dose corresponding to 0.7 mg. of histamine base.

Such a dose of histamine invariably produces a rise in urinary pH, lasting for about 2 hours, after which the reaction returns to near the original level. The duration of this (effect suggests that it is related to the gastric secretory activity. The following table is 3 typical record from a Pavlov pouch dog, showing the gastric and urinary effects.

We believe that our experiments furnish additional evidence that the alkaline tide is due to the formation of HC1 in the stomach.