Effects of Intravenous Infusion of Carbonic Anhydrase on Carbon Dioxide Tension of Alkaline Urine

¹ From the Department of Physiology, Cornell University Medical College, New York City

Five dogs were rendered hydropenic by withholding water for 20 hours and mildly alkalotic by the infusion of sodium bicarbonate intravenously in small amounts. Under these conditions alkaline urine was formed at approximately 1.0 cc/min. In 15 control periods the pCO₂ of the urine exceeded that of the plasma, the ratio averaged 2.08 ± 0.44 (S.D.) with a range of 1.45–2.79. Following the intravenous administration of 100 mg of carbonic anhydrase as a priming dose and the infusion of the enzyme at a rate of 1 mg/min., the ratio in 25 experimental periods decreased to an average of 0.988 ± 0.14 (S.D.) with a range of 0.78–1.30. We conclude that the high carbon dioxide tensions commonly observed in alkaline urines result from delayed dehydration of carbonic acid to carbon dioxide in the renal tubule.

Note:
with the technical assistance of Wanda Van Woert and Mary Ellen Parks

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