EFFECT OF INTRAVENOUS CALCIUM SALTS ON RENAL EXCRETION IN THE DOG

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Abstract
Dogs receiving steady intraven. infusions of CaCl2 or Ca gluconate for 5 hrs. showed no specific diuretic responses traceable to the amt. or rate of Ca admn. Urinary pH tended to be lower following large doses of admd. Ca than following small doses of Ca or when no Ca was infused. No significant effect of CaCl2 or Ca gluconate on alkaline reserve was found. When CaCl2 was given intraven., the velocity constant of excretion of Ca was much smaller than that of Cl and was of the same magnitude or less than the velocity constant of Cl when NaCl was given. Negative loads of Cl may be produced when CaCl2 is given. Under the conditions of these expts. there is no effective threshold of retention of Ca, and plasma concns. of this ion are apparently not regulated extensively by renal function. Relative retention of Ca to water occurs even when some solns. less concd. than plasma Ca are admd. Minimal isorrheic quantities for Ca and Cl were found to be 2 and 8 micro-equivalents per min., respectively. A non-limiting isorrheic quantity for Cl was found at approx. 70 micro-equivalents per min. Specific effects of Ca infusion on the excretion of other electrolytes were found, notably on Mg, Na, K, and PO4. The highest concn. ratio found for Ca was 4.99; the highest individual urinary concn. of Ca was 75.7 milliequivalents per liter.