Abstract
The changes of radiocalcium in the blood, liver, kidneys, femur, and bile were investigated after a single subcutaneous administration of 45CaCl2 to fasted rats. The radioactivity (dpm/g wet tissue) of 45Ca in the blood, liver, and kidneys gradually increased after the administration of 45CaCl2, while the radioactivity of 45Ca in the femur and bile was markedly elevated. The increase of radioactivity of 45Ca in the bile was greater than that in the femur. Meanwhile, the radioactivity of 45Ca in the whole liver per 100 g body weight was markedly increased 15 min after the administration of 45CaCl2. However, the radioactivity of 45Ca in the bile per 100 g body weight was only slightly increased 15 min after the administration of 45CaCl2, and then began to increase sharply. Furthermore, the excretion of radiocalcium into the urine and feces was examined after a single subcutaneous administration of 45CaCl2 to rats. The radioactivity of 45Ca in the feces was about 30 times that of the urine. It seems likely that the excretion of calcium into the feces through the bile plays a physiological role in the regulation of calcium metabolism.
