The Retention of Par enter ally Injected Calcium in Rachitic Dogs

The calcium and phosphorus balances were studied in two vitamin D free, rachitic dogs, 8 months old, given diets rich in Ca and P for 121 days. In the course of the last 113 days 36.4 g Ca (Ca glucono‐galacto‐gluconate) was injected parenterally. Practically all the injected Ca was retained. The faecal Ca exceeded food Ca by about 80 mg daily; the daily urinary Ca was 20–30 mg. The dogs gained about 20g in body Ca in the period of injections. The plasma Ca level was about 7.8 mg/100 ml and was unaffected by the Ca injections. Inorganic P in serum was about 11.5 mg/100 ml before the injections of Ca were started; following the daily Ca load, serum P was reduced to approximately 4 mg/100 ml. At the end of the experiment one dog Received vitamin D. The result was an increase in plasma Ca to 10.7 mg/100 ml in the course of 48 hours and a simultaneous reduction of the urinary Ca. Thus, vitamin D possibly affects the tubular reabsorption of Ca.