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EFFECT OF REGION OF INTESTINE AND UNSTIRRED LAYERS ON UPTAKE OF SUGARS INTO RABBIT INTESTINE
Author(s) -
Thomson A. B. R.
Publication year - 1984
Publication title -
quarterly journal of experimental physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0144-8757
DOI - 10.1113/expphysiol.1984.sp002836
Subject(s) - jejunum , ileum , fructose , galactose , chemistry , small intestine , medicine , biochemistry
The kinetic characteristics of the transport of four sugars were determined in rabbit jejunum and ileum. The effective resistance of the intestinal unstirred layer and the rates of uptake of glucose, galactose, 3‐ O ‐methyl glucose and fructose were assessed in vitro . The unstirred layer resistance was higher in jejunum than in ileum at all rates of stirring of the bulk phase. The maximal transport rates, J m d , of galactose and 3‐ O ‐methyl glucose were higher than the J m d of glucose, which in turn was higher than that for fructose. The J m d of glucose, galactose, and fructose were each lower in ileum than in jejunum, but the J m d of 3‐ O ‐methyl glucose in the ileum was similar to both regions. For the single Michaelis‐Menten model, the values of the Michaelis constant, K m , for glucose and galactose were slightly lower in the jejunum than in the ileum, whereas the value of the K m for 3‐O‐methyl glucose and for fructose were similar in the two sites. In the jejunum, the relative values of the K m were 3‐ O ‐methyl glucose = fructose 〉 galactose 〉 glucose. It is regarded that variations in sugar absorption between the jejunum and ileum are due to differences in the values of the effective resistance of the unstirred water layer, the maximal transport rate, and the Michaelis constant.