Active transport of calcium by the small intestine of the rat

¹ Department of Medicine, Columbia University College of Physicians and Surgeons; and the Presbyterian Hospital, New York City

The rates of active transport of calcium in vitro by everted gut-sacs prepared from the proximal small intestine of the rat have been quantified and expressed in absolute units. A maximal rate of transport has been measured. The bulk of the calcium transferred to the serosal surface of the gut-sac is ionized calcium, suggesting that the process is an active cation transport mechanism. The active transfer is relatively specific for Ca⁺⁺, and no significant accumulation of Mg⁺⁺, Sr⁺⁺, Ba⁺⁺ or K⁺ in the fluid bathing the serosal surface could be demonstrated. The active transport of calcium in vitro is greater with gut-sacs from growing than from older rats, and it is greater with gut-sacs from pregnant than from nonpregnant rats. The results suggest that the active transport mechanism can increase the intestinal absorption of calcium facultatively to meet the needs of the organism.

This article has been cited by other articles:

				L. V. Avioli, S. Scott, S. W. Lee, and H. F. D. Luca Intestinal Calcium Absorption: Nature of Defect in Chronic Renal Disease Science, November 28, 1969; 166(3909): 1154 - 1156. [Abstract] [PDF]

				D. Schachter, S. Kowarski, and J. D. Finkelstein Vitamin D3: Direct Action on the Small Intestine of the Rat Science, January 10, 1964; 143(3602): 143 - 144. [Abstract] [PDF]