Trypsin-Like Nature of the Pancreatic Factor That Corrects Vitamin B12 Malabsorption Associated with Pancreatic Dysfunction

Toskes, Phillip P.; Deren, Julius J.; Conrad, Marcel E.

doi:10.1172/jci107346

Cited by 43 publications

(8 citation statements)

References 11 publications

(17 reference statements)

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“…This consideration is important since it suggests that under physiological in vivo conditions, IF-Bi2 binding to ileal IF-Br2-binding sites might be different from that observed with homogeneous IF isolated from gastric juice and gastric mucosa. Other recent studies (34)(35)(36), demonstrating B12 malabsorption in humans and rats with pancreatic insufficiency and its correction with pancreatic extracts and highly purified preparations of trypsin, suggest that differences might exist between in vivo and in vitro ileal IF-B,2 binding.…”

Section: Methodsmentioning

confidence: 96%

Characterization of Ileal Vitamin B12 Binding Using Homogeneous Human and Hog Intrinsic Factors

Hooper¹,

Alpers²,

Burger³

et al. 1973

J. Clin. Invest.

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Section: Methodsmentioning

confidence: 96%

Characterization of Ileal Vitamin B12 Binding Using Homogeneous Human and Hog Intrinsic Factors

Hooper¹,

Alpers²,

Burger³

et al. 1973

J. Clin. Invest.

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“…Disruption of the mechanisms to render dietary B 12 bioavailable all involve a failure of adequate gastric acid production, disrupting the proteolytic activity of peptic digestion. 52 A similar failure of the digestive process applies in the case of chronic pancreatic disease, 53 in which the release of B 12 from salivary haptocorrin (HC) in the upper small intestine is disrupted through lack of bicarbonate and trypsin production. 54 There are some less common causes of B 12 deficiency that do not fit nicely into either category, such as infestation with the fish tapeworm, Diphyllobothrium latum, in which the degree of deficiency and hence its clinical severity can vary considerably.…”

Section: Causes Of B 12 Deficiencymentioning

confidence: 98%

Vitamin B12 deficiency from the perspective of a practicing hematologist

Green

2017

Blood

262

197

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B12 deficiency is the leading cause of megaloblastic anemia, and although more common in the elderly, can occur at any age. Clinical disease caused by B12 deficiency usually connotes severe deficiency, resulting from a failure of the gastric or ileal phase of physiological B12 absorption, best exemplified by the autoimmune disease pernicious anemia. There are many other causes of B12 deficiency, which range from severe to mild. Mild deficiency usually results from failure to render food B12 bioavailable or from dietary inadequacy. Although rarely resulting in megaloblastic anemia, mild deficiency may be associated with neurocognitive and other consequences. B12 deficiency is best diagnosed using a combination of tests because none alone is completely reliable. The features of B12 deficiency are variable and may be atypical. Timely diagnosis is important, and treatment is gratifying. Failure to diagnose B12 deficiency can have dire consequences, usually neurological. This review is written from the perspective of a practicing hematologist.

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“…Recently, T oskes el al. [20] have isolated from hog pancreatic extract a heat-labile macromolecular compound that corrects Bu malabsorption in human subjects and rats with exocrine pancreatic insufficiency. Our result is in agreement with theirs that the heated pancreatin is less effective than the native one.…”

Section: Discussionmentioning

confidence: 99%

Effect of Pancreatin on Vitamin B<sub>12</sub> Malabsorption in Patients with Total Pancreatectomy

Morishita¹,

Fujii²,

Yamamoto³

et al. 1974

Digestion

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Studies on vitamin B₁₂ absorption were performed in three patients with total pancreatectomy, three with partial pancreatectomy and a single case of pernicious anemia by a whole body counting method. All three subjects with total pancreatectomy showed _B12 malabsorption. In two out of the three patients, _B12 absorption was improved by administration of pancreatic extract, pancreatin. Another patient showed the most improved absorption when normal human gastric juice in an amount of 20 ml was administered with pancreatin because of the lack of intrinsic factor in the gastric juice. The improvable effect of pancreatin on _B12 absorption was markedly reduced by heating at 100°C for 10 min. The pancreatin, per se, had no intrinsic factor activity. Two patients with partial pancreatectomy showed normal or intermediate _B12 absorption and a slight depression of _B12 absorption by administration of pancreatin. The contamination by vitamin _B12 in pancreatin might have been responsible for reduction of _B12 absorption. The data obtained indicated that the normal secretory functions of both the pancreas and gastric intrinsic factor were necessary for an optimal _B12 absorption. The possible mechanisms to account for the beneficial effects of pancreatin on vitamin _B12 absorption are discussed.

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Trypsin-Like Nature of the Pancreatic Factor That Corrects Vitamin B12 Malabsorption Associated with Pancreatic Dysfunction

Cited by 43 publications

References 11 publications

Characterization of Ileal Vitamin B12 Binding Using Homogeneous Human and Hog Intrinsic Factors

Characterization of Ileal Vitamin B12 Binding Using Homogeneous Human and Hog Intrinsic Factors

Vitamin B12 deficiency from the perspective of a practicing hematologist

Effect of Pancreatin on Vitamin B<sub>12</sub> Malabsorption in Patients with Total Pancreatectomy

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