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Studies on Human Gastric Intrinsic Factor OBSERVATIONS ON ITS POSSIBLE ABSORPTION AND ENTEROHEPATIC CIRCULATION
Author(s) -
Ardeman S.,
Chanarin I.,
Berry Valerie
Publication year - 1965
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1965.tb00078.x
Subject(s) - intrinsic factor , enterohepatic circulation , medicine , endocrinology , vitamin , vitamin b12 , cyanocobalamin , kidney , biology , chemistry , metabolism
U nder physiological conditions Intrinsic Factor secreted by the cells of the gastric mucosa is required for the uptake of vitamin B 12 by the small intestine. Vitamin B 12 passes to the blood, reaches the liver as well as other organs, and some is re‐excreted into the bile (Grasbeck, Nyberg and Reizenstein, 1958). Whether vitamin B 12 is accompanied by Intrinsic Factor on its passage into the blood and into the bile or whether Intrinsic Factor does not pass beyond the intestinal wall is uncertain. Miller and Hunter (1957) have demonstrated that not only does Intrinsic Factor enhance the vitamin B 12 uptake by gut but it will also promote the attachment of vitamin B 12 to serum, liver, kidney and other tissues. It has been suggested that vitamin B 12 and Intrinsic Factor, but not vitamin B 12 alone, is required to restore normoblastic haemopoiesis in a culture of megaloblastic marrow (Lajtha, 1950; Callender and Lajtha, 1951; Pendl, Franz and Hunkel‐Trees, 1958). Toporek (1961) has shown that Intrinsic Factor perfused through a rat liver is re‐excreted in an active form into the bile and Herbert and Kaplan (1961) have reported evidence suggesting that Intrinsic Factor, like vitamin B 12 (Grasbeck et al. , 1958) takes part in an entero‐hepatic circulation. Further Gulberg and Kistner (1963) have found that hog bile contains a fraction showing the same immunological behaviour as the main vitamin B 12 binding component of hog Intrinsic Factor. It is likely that the haematological relapse of patients with pernicious anaemia treated with oral vitamin B 12 and hog Intrinsic Factor preparations is due to the development of antibodies against hog Intrinsic Factor suggesting absorption of at least some of this material (Schwartz, 1962). On the other hand, Cooper and Castle (1960) found evidence for the release of vitamin B 12 from Intrinsic Factor at the gut wall. Taylor and Medenica (1962) found that the uptake of vitamin B 12 by rat tissues, particularly the liver, was independent of a source of Intrinsic Factor and others have failed to substantiate an Intrinsic Factor requirement for the maturation of a megaloblastic marrow culture (Reisner and Swan, 1954; Carrara, Taglioretti and Eridani, 1960). The large molecular weight suggested for Intrinsic Factor by some workers (Bromer and Davisson, 1961) does not favour its transport beyond the gut wall, at least in the undegraded form. The purpose of the present study was, firstly, to obtain evidence for or against transport of Intrinsic Factor into the blood and, secondly, to determine whether Intrinsic Factor, like vitamin B 12 , takes part in an entero‐hepatic circulation.