Abstract
Different amounts of Na 9, 77, 161, and 262 mEq/day, were administered orally to 3 healthy ileostomized subjects with each study period lasting 6 days. The small intestine has a limited capacity to conserve Na. Thus, on the 9mEq/day Na intake, Na excretion continued via the ileostomy and far exceeded the amount ingested; the urinary Na output fell rapidly to 10mEq/day or less within a 3-day period in all subjects. Because of the ideal Na loss, clinical evidence of Na depletion occurred in one subject. The mean ileal Na output and concentration for the group were lowest on the 9mEq/day Na intake, whereas potassium concentration and output rose; these changes suggested than an endogenous mineralocorticoid response may have occurred. As 77 mEq/day and the larger quantities of Na were ingested, the ileal excreta total weight (grams per day), the water content (grams per day), and the Na excretion (milliequivalents per day) increased, whereas the dry weight (grams per day) remained constant. However, the Na concentration in milliequivalents per kg or milliequivalents per liter did not change. Such findings suggest an osmotic cathartic effect by the larger amounts of NaCl. Fat and N excretion remained unchanged throughout the study.