Rat Gastric Acid Research Articles

Inhibition of Vitamin B-12 Absorption by Bile.

Summary1. In the intact rat the presence of bile in the small intestine inhibits B12 absorption. 2. The inhibitory effect of bile is prevented by simultaneous addition of rat gastric juice.

Vitamin B12 absorption in rats, studied by a ‘loop’ technique

A technique to prepare an intestinal loop in situ in rats is described for the study of the effect of intrinsic factor (IF) on the absorption of vitamin B12 and of the site of absorption. It was found that a) the site of absorption of vitamin B12 is the smal intestine and, particularly, the middle portion; b) a saline extract of rat stomach mucosa, as well as rat gastric juice, when mixed with a low test dose of vitamin B12, markedly increased the absorption of vitamin B12 by the loop. A quantitative relationship was demonstrated between absorption and vitamin B12-binding power of such an extract. However, a purified hog IF did not enhance the absorption of vitamin B12 and c) two different mechanisms for the absorption of vitamin B12 are suggested. One operates when a small physiological dose is administered; the absorption can be enhanced by co-administration of IF and be inhibited by ethylenediaminetetraacetate (EDTA). The other operates when a high dose is given; the absorption under such conditions is not affected either way by the administration of IF or EDTA.

Effect of intrinsic factor on vitamin B12 uptake by rat intestine in vitro.

SummarySacs of everted small intestine of the rat incubated in bicarbonate-saline containing glucose and B12 showed only a very small B12 uptake in the absence of a source of intrinsic factor. In the presence of neutralized rat gastric juice the stimulation of B12 uptake was 10- to 25-fold. No B12 appeared on the serosal side of the preparation. Stimulation of B12 uptake was most marked in segments of intestine taken from the midportion of the small intestine. Evidence is presented that neither B12 nor intrinsic factor when added alone are adsorbed to the intestinal wall but must be present simultaneously to give B12 uptake.

Mechanism of intrinsic factor action in the gastrectomized rat.

1. In experiments with gastrectomized rats: (a) The probable species specificity of rat intrinsic factor was demonstrated by the failure of a highly purified preparation of hog intrinsic factor to increase the absorption of Co60-B12. (b) In consonance with previous observations in pernicious anemia, acidification (pH 1.85) of a mixture of Co60-B12 and homogenized rat stomach inhibited the absorption of Co60-B12. (c) In contrast to previous observations in pernicious anemia, separate serial administration of Co60-B12 and rat gastric juice failed to show that rat intrinsic factor was more effective in promoting the absorption of Co60-B12 when it preceded than when it followed the Co60-B12. Indeed, no certain effect of rat intrinsic factor was detected whether it preceded or followed the Co60-B12 by as short an interval as 30 minutes. 2. In experiments with paired isolated loops of small bowel with intact blood supply created in previously gastrectomized rats: (a) The radioactivity of the wall of the loop perfused with Co60-B12 and rat gastric juice was greater than that of the paired loop perfused with Co60-B12 and rat gastric juice previously heated to destroy its intrinsic factor activity. No consistent difference was observed with heated or unheated human gastric juice. (b) The absorption of Co60-B12 was greater when labelled rather than unlabelled vit. B12 in equal amounts had saturated the binding capacity of rat gastric juice before admixture with an equal amount of the other form of vit. B12 just before the intestinal perfusion. 3. In conclusion, binding of vit. B12 is an important, perhaps indispensable, aspect of the function of intrinsic factor.

Enhanced absorption of vitamin B12 in gastrectomized rat by rat intrinsic factor.

Conclusions1. The percentage excretion of radioactivity in the feces of normal and of totally gastrectomized rats, following administration of a single dose of 0.015 μg Co60-B12, was determined by scintillation counting. 2. The gastrectomized rats apparently were unable to absorb the labelled vit. B12 (100% fecal excretion). 3. Simultaneous administration of homogenized rat stomach or of rat gastric juice but not of human gastric juice or of an extract of hog stomach mucosa reproduced in the gastrectomized rat the capacity of the normal rat to absorb the test dose of Co60-B12 administered (60% fecal excretion). 4. The rat, like man, secretes intrinsic factor largely, if not exclusively, into the stomach; but sources of human and hog intrinsic factor possess little or no activity in the rat. 5. The observations of Watson and Florey indicate that in the rat the secretion of intrinsic factor is probably confined to the distal secretory portion of the stomach.

Effect of osmotic gradients on water transport, hydrogen ion and chloride ion production in the resting and secreting stomach.

ArticleEffect of Osmotic Gradients on Water Transport, Hydrogen Ion and Chloride Ion Production in the Resting and Secreting StomachWarren S. Rehm, Hilda Schlesinger, and Warren H. DennisWarren S. RehmFrom the Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky, Hilda SchlesingerFrom the Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky, and Warren H. DennisFrom the Department of Physiology, University of Louisville School of Medicine, Louisville, KentuckyPublished Online:30 Nov 1953https://doi.org/10.1152/ajplegacy.1953.175.3.473MoreSectionsPDF (3 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Download PDF FiguresReferencesRelatedInformation Cited ByReal Time Measurements of Water Flow in Amphibian Gastric GlandsJournal of Biological Chemistry, Vol. 282, No. 18[31] Direct current electrical measurement in epithelia: Steady-state and transient analysisInhibition of acid secretion of fundus of Rana pipiens with a high concentration of potassium on the secretory sideBiochimica et Biophysica Acta (BBA) - Biomembranes, Vol. 899, No. 1A study of dynamic membrane phenomena during the gastric secretory cycle: Fusion, retrieval and recycling of membranesThe Journal of Membrane Biology, Vol. 80, No. 2The fine structure of the gastric epithelium of the rainbow trout, Salmo gairdneri, RichardsonJournal of Fish Biology, Vol. 19, No. 6Gastric SecretionIon and Water Transport in Gastric MucosaSodium and Potassium27 April 2009 | Nutrition Reviews, Vol. 34, No. 8Hyperosmotic instillation of rat stomachLife Sciences, Vol. 17, No. 3The Effects of Large Osmolality Variations on the Gastric Mucosal Ion PermeabilityActa Physiologica Scandinavica, Vol. 90, No. 1Intramucosal gastric acid concentration determined by glass microelectrode techniqueBiochimica et Biophysica Acta (BBA) - Biomembranes, Vol. 291, No. 1Gastric Absorption of L(+) and D(-) Lactic Acid and their Effects on the Transmucosal Ion Transport in Innervated, Non-secreting Cat StomachsActa Physiologica Scandinavica, Vol. 85, No. 3Proton TransportA model to explain uphill water transport in the mammalian stomachJournal of Theoretical Biology, Vol. 27, No. 3Ionenkonzentration, Osmolarität und Flüssigkeitssekretion im Labmagen von Ziegen13 May 2010 | Zentralblatt für Veterinärmedizin Reihe A, Vol. 15, No. 7The relationship between osmolality and electrolytes in rat gastric juice following histamine and insulin hypoglycaemiaEuropean Journal of Pharmacology, Vol. 3, No. 3Ionic constituents and osmolality of gastric and small-intestinal fluids after eatingThe American Journal of Digestive Diseases, Vol. 11, No. 7Are Surface Epithelial Cells Necessary for Gastric Acid Secretion?Gastroenterology, Vol. 37, No. 2Microscopic Dimensions of the Pit Region of the Dog's Gastric MucosaGastroenterology, Vol. 35, No. 3Some Reflections on Gastric SecretionGastroenterology, Vol. 33, No. 1Water Permeability of the Isolated Stomach of the MouseActa Physiologica Scandinavica, Vol. 36, No. 3 More from this issue > Volume 175Issue 3November 1953Pages 473-486 Copyright & PermissionsCopyright © 1953 by American Physiological Societyhttps://doi.org/10.1152/ajplegacy.1953.175.3.473PubMed13114431History Received 27 July 1953 Published online 30 November 1953 Published in print 30 November 1953 Metrics