Evidence that Pancreatic Proteases Enhance Vitamin B12 Absorption by Acting on Crude Preparations of Hog Gastric Intrinsic Factor and Human Gastric Juice

Abstract 1. Normal gastric juice (intrinsic factor) and vitamin B12 together form a thermolabile hemopoietic factor which ripens megaloblasts in vitro, both gastric juice and B12 alone being inactive. 2. The hemopoietic factor in normal serum which ripens megaloblasts in vitro also appears to be thermolabile, heating to 56 C. for 2 hours destroying some of its activity. 3. The relationship of these factors is discussed and an extra-gastric as well as a gastric source of intrinsic factor is postulated.

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Vitamin B12 Malabsorption Due to Intrinsic Factor Deficiency in Indian Subjects

Blood ◽

10.1182/blood.v40.5.747.747 ◽

1972 ◽

Vol 40 (5) ◽

pp. 747-753 ◽

Cited By ~ 3

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.

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The Vitamin B12-Binding Principle of Human Gastric Juice: Influence of Ph on the Bacterial Adsorption of Free and Bound B12

Scandinavian Journal of Clinical and Laboratory Investigation ◽

10.3109/00365515709088113 ◽

1957 ◽

Vol 9 (1) ◽

pp. 50-53 ◽

Cited By ~ 3

Author(s):

R. Gräsbeck

Keyword(s):

Vitamin B12 ◽

Gastric Juice ◽

Human Gastric Juice ◽

Bacterial Adsorption ◽

Influence Of Ph

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Intestinal distribution of intrinsic factor and vitamin B12 absorption

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1965.208.1.14 ◽

1965 ◽

Vol 208 (1) ◽

pp. 14-17 ◽

Cited By ~ 5

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.

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