In vitro effect of duodenal juice on R binders cobalamin complexes in subjects with pancreatic insufficiency: correlation with cobalamin absorption.
نویسندگان
چکیده
Absorption of cobalamin free or bound to chicken serum was assessed in nine patients with pancreatic insufficiency. Simultaneously the in vitro effect of duodenal juice collected from six patients and seven controls was tested on labelled cobalamin complexed to chicken serum or to R salivary binder. Malabsorption of free cobalamin was observed in one of nine patients and in four of nine patients when cobalamin was administered bound to chicken serum. The in vitro effect of duodenal juice on cobalamin complexed to chicken serum or to R salivary binder was studied: the percentage of free cobalamin released was significantly decreased in pancreatic insufficiency compared with controls whatever the binder used; the degradation of R salivary binder was different in pancreatic insufficiency and in controls. Despite the in vitro abnormalities observed in pancreatic insufficiency, these did not correlate with the in vivo absorption of cobalamin which was often normal in our patients.
منابع مشابه
Human Intestine INHIBITED COBALAMIN ABSORPTION IN EXOCRINE PANCREATIC DYSFUNCTION
upper gastrointestinal tract are essential determining factors for transport and absorption of cobalamin in man. Jejunal fluid was aspirated from healthy human volunteers after administration of cyano[57Co]cobalamin preparations. Immunochemical analysis of the aspirates demonstrated that all isotopic vitamin was transferred to a protein that is identical to the gastric intrinsic factor in terms...
متن کاملCobalamin malabsorption due to nondegradation of R proteins in the human intestine. Inhibited cobalamin absorption in exocrine pancreatic dysfunction.
In vivo studies demonstrate that the pancreatic enzymes and the ionic environment in the upper gastrointestinal tract are essential determining factors for transport and absorption of cobalamin in man. Jejunal fluid was aspirated from healthy human volunteers after administration of cyano[57Co]cobalamin preparations. Immunochemical analysis of the aspirates demonstrated that all isotopic vitami...
متن کاملCorrection of cobalamin malabsorption in pancreatic insufficiency with a cobalamin analogue that binds with high affinity to R protein but not to intrinsic factor. In vivo evidence that a failure to partially degrade R protein is responsible for cobalamin malabsorption in pancreatic insufficiency.
In vitro studies indicate that [(57)Co]cobalamin (Cbl) is preferentially bound to salivary R protein as opposed to intrinsic factor (IF) and that [(57)Co]Cbl bound to R protein is not transferred to IF at either pH 2 or pH 8. Incubation of R protein-[(57)Co]Cbl with pancreatic proteases causes a partial degradation of the R protein moiety and a rapid transfer of [(57)Co]Cbl to IF. We have postu...
متن کاملRadioimmunoassay for assessing exocrine pancreatic insufficiency, based on the differential enzymatic degradation of cobalamin-binding proteins.
Pancreatic proteases degrade the protein moiety of the R protein-cobalamin complex but not the intrinsic factor-cobalamin complex. Accordingly, we used these two proteins as substrates in an in vitro enzymatic assay to assess pancreatic function by incubating basal jejunal fluids with a mixture of intrinsic factor and cyano[57Co]cobalamin coupled to R-type protein and then using immunoprecipita...
متن کاملHomocysteine, Cobalamin and Folate Status and their Relations to Neurocognitive and Psychological Markers in Elderly in Northeastern of Iran
Objective(s): Incidence of neurocognitive and psychological disorders may be related to serum homocystein (Hcy), cobalamin (vitamin B12 ) and folate levels in old people. The aim of this study was to assess the relation between Hcy, cobalamin, folate and neurocognitive and/or psychological disorders in the elderly. Materials and Methods: In this cross-sectional study, 280 subjects with ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Gut
دوره 28 1 شماره
صفحات -
تاریخ انتشار 1987