Variability of potassium concentration in gastric secretion

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Abstract
The work of Gray and Bucher (Am. J. Physiol. 133: 542, 1941), which led them to the conclusion that the concentration of K in histamine-stimulated gastric secretion from canine vagotomized pouches is constant around 7.4 mEq/l., was repeated with only minor modification. The stimulus was administered either in a series of small subcutaneous doses repeated every 10 minutes, or in a single larger dose injected after termination of the former. Regardless of procedure, the experiments revealed a range in [K]-values of considerable magnitude, extending both above and below the level characteristic of normal canine serum; for the entire study, the lowest concentration observed was 1.6, the highest 11.2 mEq/l. Although these variations were systematic, they were not definitively correlated with acidity, [Na] or [Cl]. Hence, the inference that 7.4 mEq/l. characterizes the [K] of both the primary acid secretion and the non-acid mucous secretion is likewise invalidated. This conflict between our data and those obtained by Gray and Bucher is shown to result from two defects in their experimental design: a) they discarded all secretion collected during the first 60-minutes—an interval which gives rise to many of the [K] values well above 7.4 mEq/l.; and b) they used pooled specimens, regardless of experiment and—in most cases—of dog. The significance of these variations in [K] will be considered in a subsequent publication.