URINE TITRATABLE ACIDITY AND AMMONIA EXCRETION DURING HYPOTHERMIA

Hydrogen ion secretion by the kidneys of anesthetized hypothermic dogs was measured to ascertain if the hypothermic kidney helps to compensate for the acidosis which develops during exposure to cold. Artificial respiration was not used. Total hydrogen ion excretion was measured as the sum of total titratable acid and ammonia excreted. Though anaerobic arterial pH, corrected to body temperature, fell significantly from 7.41 during control to 7.27 at 27 degrees C., urinary pH remained at control levels of approximately 6.8. Neither titratable acid nor ammonia excretion increased in response to the hypothermic acidosis as would have occurred during normothermia with a similar low pH. Total titratable acid excretion fell from a control value of 0.011 mEq.min. to 0.005 mEq.min. at 27 degrees C. Ammonia excretion, after a mild increase from a control value of 0.008 mEq.min., fell to 0.006 mEq.min. at 27 degrees C.