Rates of insorption of sodium and potassium from stomachs of rats

¹ Mayo Clinic and Mayo Foundation, Rochester, Minnesota

This study was undertaken to determine rates of insorption of radiosodium and radiopotassium from secreting and nonsecreting stomachs of rats. The methods employed have been described previously. Insorption of radiosodium from gastric contents to blood was always faster in nonsecreting than in acid-secreting stomachs. At the end of 15, 30, and 45 min the mean percentages insorbed from stomachs secreting acid were 1.6, 3.1, and 4.5, whereas from stomach not secreting acid the mean percentages were 5.8, 9.3 and 11.7, respectively. In contrast, the rate of insorption of radiopotassium was unaffected by presence or absence of acid. Its rate of insorption was uniformly low and about equal to the rate of insorption of radiosodium from the secreting stomach. The results demonstrate that the rat's stomach, like that of man and dog, offers a barrier to insorption of sodium which is more pronounced when acid is being secreted and that insorption of potassium, though slow, is unaffected by acid and most likely is independent of insorption of sodium.