Intestinal distribution of intrinsic factor and vitamin B12 absorption

1965 ◽  
Vol 208 (1) ◽  
pp. 14-17 ◽  
Author(s):  
Kunio Okuda ◽  
Katsumi Sasayama
Keyword(s):  
Small Intestine ◽  
Vitamin B12 ◽  
Large Intestine ◽  
Intrinsic Factor ◽  
Vitamin B ◽  
Vitamin B12 Absorption ◽  
Small Intestine Absorption

Evidence is presented that intrinsic-factor (IF) activity is present in the small intestine as far down as the ileal end. Physiologic doses of radioactive vitamin B12 without IF were applied directly into various levels of the intestine by surgical and other means in man and rats, and significant absorption was obtained from the small intestine. Absorption inhibition by ethylenediaminetetraacetate and its counteraction by Ca ion demonstrated that such absorption was dependent on IF action. The large intestine was shown to be incapable of physiologic absorption of vitamin B12, and IF was totally ineffective. It is proposed that physiologically, gastric IF descends with some activity in the small intestine, where more of the food vitamin B12 is liberated by digestion and subjected to IF.

Vitamin B12 absorption in dogs with chronic isolated intestinal loops

1969 ◽  
Vol 47 (6) ◽  
pp. 497-504
Author(s):  
R. M. Taylor ◽  
J. A. Hildes ◽  
J. F. Lind
Keyword(s):  
Small Intestine ◽  
Vitamin B12 ◽  
Intrinsic Factor ◽  
Cellular Mechanism ◽  
Vitamin B ◽  
Absorption Factor ◽  
Ileal Mucosa ◽  
Ileal Loop ◽  
Simultaneous Absorption ◽  
Vitamin B12 Absorption

The absorption of physiological amounts of vitamin B12 is thought to occur only from the ileum, but the nature of the mechanism involved has not been established. A method utilizing the detection of radioactive vitamin B12 in plasma was used to investigate the mechanism of vitamin B12 absorption in dogs with isolated Thiry–Vella loops of small intestine, either ileum or jejunum. An animal with a Thiry–Vella loop of the entire ileum failed to absorb orally administered vitamin B12, but did absorb the vitamin from the isolated ileal loop when it was given with intrinsic factor, but not when given without. Attempts to restore absorption of orally administered vitamin B12 by the administration of ileal juice (either resting or stimulated), by the administration of an extract of ileal mucosa, or by the simultaneous absorption of non-radioactive vitamin B12 from the ioslated loop, all failed. In contrast, the animal with a jejunal Thiry–Vella loop absorbed vitamin B12 given orally but not when administered into the isolated jejunum alone, in combination with intrinsic factor, or with intrinsic factor and ileal juice. Under the conditions of these experiments the results confirm that vitamin B12 absorption is limited to the ileum, but fail to provide support for the hypothesis that the ileum liberates, either locally or systemically, a vitamin B12 absorption factor. Thus the hypothesis that ileal mucosa contains a special cellular mechanism for vitamin B12 absorption gains indirect support from these results.

scholarly journals The response to prednisolone in atrophic gastritis: a possible effect on non-intrinsic factor-mediated vitamin B12 absorption

Gut ◽  
1973 ◽  
Vol 14 (1) ◽  
pp. 13-19 ◽  
Author(s):  
R. G. Strickland ◽  
J. M. Fisher ◽  
K. Lewin ◽  
K. B. Taylor
Keyword(s):  
Vitamin B12 ◽  
Atrophic Gastritis ◽  
Intrinsic Factor ◽  
Vitamin B12 Absorption

Some species differences in the intrinsic factor stimulation of B12 uptake by small intestine in vitro

1959 ◽  
Vol 197 (4) ◽  
pp. 926-928 ◽  
Author(s):  
T. Hastings Wilson ◽  
Elliott W. Strauss
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Species Differences ◽  
Intrinsic Factor ◽  
Vitamin B ◽  
Guinea Pig Ileum ◽  
Rat Intestine ◽  
Intrinsic Factors ◽  
Stimulation Of

Sacs of everted small intestine from a variety of animals were incubated in bicarbonate-saline containing vitamin B12 with and without intrinsic factor (IF). B12 uptake by rat intestine was stimulated only by its own intrinsic factor. Guinea pig ileum responded to all intrinsic factors tested (guinea pig, rat, hog, hamster, human being and rabbit). The intestines of hamster and rabbit were intermediate in specificity, responding to some, but not all, of the IF preparations. Species differences occur in both the intestine and intrinsic factor preparations. The guinea pig ileum was suggested as a possible assay for both hog and human IF.

scholarly journals Vitamin B12 Malabsorption Due to Intrinsic Factor Deficiency in Indian Subjects

Blood ◽  
1972 ◽  
Vol 40 (5) ◽  
pp. 747-753 ◽  
Author(s):  
H. G. Desai ◽  
F. P. Antia
Keyword(s):  
Vitamin B12 ◽  
Pernicious Anemia ◽  
Indian Population ◽  
Intrinsic Factor ◽  
Subacute Combined Degeneration ◽  
Factor Deficiency ◽  
Vitamin B12 Absorption ◽  
Intrinsic Factor Deficiency ◽  
Intrinsic Factor Antibody ◽  
Vitamin B12 Malabsorption

Abstract Sixteen patients (from Bombay) with severe vitamin B12 malabsorption due to intrinsic factor deficiency, presenting as subacute combined degeneration of the cord (7), tropical sprue (3), anemia (2), thyrotoxicosis (2), diabetes mellitus (1), and pain in the abdomen (1), are reported. The difficulties of establishing a definite diagnosis of pernicious anemia in Indian population are described. The lower incidence of circulating intrinsic factor antibody (IFA) in Indian patients with histamine-fast achlorhydria and poor vitamin B12 absorption is emphasized. The necessity of separating atrophic gastritis, with severely impaired vitamm B12 absorption, from pernicious anemia on the basis of absence or presence of IFA in serum and/or gastric juice cannot be overemphasized.

Factors controlling B12 uptake by intestinal sacs in vitro

1960 ◽  
Vol 198 (1) ◽  
pp. 103-107 ◽  
Author(s):  
Elliott W. Strauss ◽  
T. Hastings Wilson
Keyword(s):  
Small Intestine ◽  
Low Temperature ◽  
Guinea Pig ◽  
Calcium Ion ◽  
Intrinsic Factor ◽  
Intestinal Wall ◽  
Vitamin B ◽  
Anaerobic Conditions ◽  
Intestinal Uptake

Sacs of everted small intestine were incubated in bicarbonate-saline containing radioactive vitamin B12 with or without a source of gastric intrinsic factor (IF). In both the hamster and guinea pig the lowest ileum was most active in B12 uptake in the presence of intrinsic factor, the upper jejunum showing little or no uptake. Low temperature and anaerobic conditions completely abolished the stimulatory effect of IF on B12 uptake. Intrinsic factor did not bind to the intestinal wall in the absence of B12 (even in the presence of calcium ion) as the IF activity could be completely removed by gentle washing of the tissue. The vitamin and intrinsic factor must be present together to cause intestinal uptake of B12.

Effect of Rat Intrinsic Factor on Vitamin B12 Absorption in Pernicious Anemia

Science ◽  
1957 ◽  
Vol 126 (3273) ◽  
pp. 558-558 ◽  
Author(s):  
J. ABELS ◽  
M. G. WOLDRING ◽  
J. J. M. VEGTER ◽  
H. O. NIEWEG
Keyword(s):  
Vitamin B12 ◽  
Pernicious Anemia ◽  
Intrinsic Factor ◽  
Vitamin B12 Absorption
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