This study clearly demonstrated that the accumulation of 135m Ba in the gastrointestinal tract varies from species to species. A separate study showed that the plasma concentration of barium with time in different species including man is similar. The percentage of injected activity in the gastrointestinal tract in mice and rats at 1 day was found to be 0.4 and 1.72, respectively. The excretion of 135mBa through the feces at 1 day in mice and rats was about 12% and in dogs it was about 3%. In humans it was found to be 15-18%. That the amount of secretion of 135mBa into the gastrointestinal tract of humans is higher than that in animals was evident from scintiscanning images. These studies show that the gastrointestinal excretion of barium in humans is greater than strontium. It could be postulated that among the alkaline earth metals, the higher the atomic weight of the element the higher is the excretion through the gastrointestinal tract. For example, the excretion of barium through the gastrointestinal tract is 5 times higher than strontium. The excretion of radium through the gastrointestinal tract is 6 times higher than strontium and 8% higher than barium. Whereas most of the beryllium whose atomic weight is only 9 is excreted in the urine. It was shown that the excretion following intravenous administration is mainly via the bowel, the ratio of the intestinal to the renal clearance being 9 for barium and 36 for radium.4 The excretion of barium through the gastrointestinal tract in rats had two components for half-time of clearance of 6 and 36 hours, respectively. In humans the food remains in small intestine for 4 hours and in the large intestine for 37 hours. This indicates the physiology of the gastrointestinal tract in rats and humans to be similar. Also it could be assumed that the barium ions once secreted into the gastrointestinal tract are bound to the fecal matter particularly to anions such as sulfates. Because soluble sulfate in water such as magnesium or sodium sulfate is rapidly administered orally as an antidote for barium poisoning7. Barium sulfate is benign and used extensively in diagnostic radiology for visualizing the upper and lower gastrointestinal tracts.
|Original language||English (US)|
|Title of host publication||American Journal of Proctology Gastroenterology and Colon and Rectal Surgery|
|Number of pages||5|
|State||Published - 1981|
ASJC Scopus subject areas