Trypsin-Like Nature of the Pancreatic Factor That Corrects Vitamin B<sub>12</sub> Malabsorption Associated with Pancreatic Dysfunction

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

doi:10.1172/JCI107346

^{Walter Reed Army Institute of Research, Walter Reed Army Medical Center, Washington, D. C. 20012}

^{Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104}

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^{Walter Reed Army Institute of Research, Walter Reed Army Medical Center, Washington, D. C. 20012}

^{Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104}

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^{Walter Reed Army Institute of Research, Walter Reed Army Medical Center, Washington, D. C. 20012}

^{Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104}

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Published in Volume 52, Issue 7 on July 1, 1973
J Clin Invest. 1973;52(7):1660–1664. https://doi.org/10.1172/JCI107346.
© 1973 The American Society for Clinical Investigation

Published July 1, 1973 - Version history

Hog pancreas was subfractionated and assessed for its ability to correct vitamin B₁₂ malabsorption in patients with pancreatic dysfunction and in rats with partial pancreatic extirpation. The constituent obtained from the pancreas that increased vitamin B₁₂ absorption in both humans and rats was soluble at 50,000 g, heat labile, acid stable, and approximately 20,000-25,0000 in molecular weight. The active subfractions contained tryptic and chymotryptic but no amylase or lipase activity. Thrice-crystallized trypsin corrected the vitamin B₁₂ malabsorption in both patients with pancreatic insufficiency and in rats with subtotal pancreatectomy. These data indicate that pancreatic proteolytic enzymes—in particular, trypsin—are necessary for optimal vitamin B₁₂ absorption.