Glucose and fructose absorption in idiopathic steatorrhoea.

Holdsworth, C D; Dawson, A. M.

doi:10.1136/gut.6.4.387

Cited by 50 publications

(24 citation statements)

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“…Ifthe assumptions ofthe simulation are correct, then the difference between the active coeliac anid control groups cannot be explained solely by difference in unstirred layer thickness, but also incorporates an approximate four-fold difference in Jmax. 873 N. W. Read, D. C. Barber, R. J. Levin, and C. D. Holdsworth remain fixed at 5 mM, the separation between the active coeliac and the normal group would indicate an approximately four-fold difference in Jmax corresponding to that estimated experimentally in man (Schedl and Clifton, 1961;Holdsworth and Dawson, 1965).…”

Section: Predictionsmentioning

confidence: 86%

“…The lines are clearly well separated confirming that the differences in Apparent Km between the active coeliac and control group clearly cannot be explained by the changes in the thickness of the unstirred layer alone. Moreover, if we accept that the Jmax in coeliac disease is only a fraction of that in health (Schedl and Clifton, 1961; Holdsworth and Dawson, 1965), then it is unnecessary to postulate any change in the real affinity of the glucose carrier …”

Section: Predictionsmentioning

confidence: 99%

“…Although both Jmax and 'd' are reduced in coeliac disease, reliable extraction of Real Km from chemical absorption data(Schedl and Clifton, 1961;Holdsworth and Dawson, 1965) using Parson's formula is still impossible. However, it is remarkable that as a result of the disease process the Apparent Km in this condition must be much closer to the Real Km than that found in health.…”

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confidence: 99%

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Unstirred layer and kinetics of electrogenic glucose absorption in the human jejunum in situ

Read¹,

Barber²,

Levin³

et al. 1977

Gut

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SUMMARY Using an electrical technique we estimated the thickness of the unstirred layer in the human jejunum during kinetic studies of electrogenic glucose absorption. The unstirred layer in seven healthy volunteers (632 + 24 ,um: mean + SEM) was significantly thicker than in 10 patients with active coeliac disease (442 + 23 ,um) but not significantly different in seven patients who had responded to treatment by gluten withdrawal (585 + 49 ,um). There were similar differences in the values of 'Apparent Km' for electrogenic glucose absorption between healthy control subjects (36 + 6 mM) active coeliac patients (11 1 mM) and treated coeliac patients (31 + 5 mM). The changes in PDmax however, showed a different pattern. The PDmax in the active coeliac group (6f8 + 0 7 mV) was lower than in controls (7-6 + 0-6 mV) but not significantly so, while the PDmax in the treated coeliac group (10-6 + 0 9 mV) was significantly higher than in both the active coeliac and control groups. It should be noted that both operational kinetic parameters obtained in the present study are much lower than those obtained previously (Read et al., 1976b) because of the use of siphonage. Analysis of the results using a computer simulation indicates that the reduction in Apparent Km in active coeliac disease can be caused by the interaction of the decreased maximal absorption rate for glucose (Jmax) with the attenuated unstirred layer. In these circumstances it is not necessary to postulate any change in the affinity of the transport mechanism for glucose ('Real Km'). It is remarkable that the disease process produces an Apparent Km which is much closer to the Real Km than that found in health.Part 1: Measurement of functional unstirred layer thicknessWe have previously described a technique for measuring changes in transmural potential difference (PD) across the human jejunum in vivo in response to infusion of solutions containing glucose (Read et al., 1974). Using this technique we observed that the operational kinetic parameters ('Apparent Km', PDmax) for the active electrogenic component of glucose absorption were significantly lower in untreated coeliac disease than in healthy controls (Read et al., 1976b). It is possible that these results could be caused by differences in the thickness of the layer of unstirred fluid which lies adjacent to the mucosal epithelium.In this present paper we used an electrical technique for estimating the thickness of this unstirred

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Section: Predictionsmentioning

confidence: 86%

Section: Predictionsmentioning

confidence: 99%

mentioning

confidence: 99%

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Unstirred layer and kinetics of electrogenic glucose absorption in the human jejunum in situ

Read¹,

Barber²,

Levin³

et al. 1977

Gut

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“…Those amino acids which reach the large intestine are decarboxylated, transaminated or chemically altered by bacterial enzyme action. A very marked impairment in the rate of monosaccharide absorption has been demonstrated in adult coeliac disease when the jejunal mucosa is damaged (Holdsworth & Dawson, 1965); a similar impairment in the rate of amino acid absorption probably exists. The mucosa is damaged in severe malnutrition; in Kwashiorkor changes of the jejunal mucosa, which are associated with a greatly decreased absorptive area, have been demonstrated (Burman, 1965;Stanfield, Hutt & Tunnicliffe, 1965).…”

Section: Discussionmentioning

confidence: 99%

Impairment of glycine absorption by glucose and galactose in man

Cook¹

1971

The Journal of Physiology

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SUMMARY1. In order to investigate a possible competition for intestinal transport between amino acids and monosaccharides in man, iso-osmotic solutions containing (A) 100 m-mole glycine 1.-i, (B) 100 m-mole glycine and 200 mmole monosaccharide (glucose or galactose) 1.-i, and (C) 200 m-mole monosaccharide 1.-i, were successively perfused into the upper jejunum of twelve African Zambian patients. None had clinical evidence of malnutrition or small-intestinal disease. By using a double-lumen tube and by reference to a non-absorbable marker (polyethylene glycol, 4000), the rates of absorption of these substances have been calculated for a 30 cm jejunal segment.2. The presence of glucose and galactose produced a significant impairment (up to 50 %) in the rate of absorption of glycine. There was also a significant decrease in the uptake of both monosaccharides from the solutions in which glycine was also present. 3. If this observation also applies to other amino acids it could have a practical value in population groups living on high carbohydrate diets with a marginal concentration of some essential amino acids. It could have special importance when the jejunal mucosa is damaged in severe malnutrition or gastrointestinal infection. This impairment of amino acid uptake may explain the very high incidence of genetically determined lactasedeficiency in Africa.

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“…So beruht die reduzierte K ohlenhydratausnutzung sowohl au f einem Unverm ö gen, M onosaccharide zu resorbieren, als auch au f einem Mangel an Disaccharidasen in der D arm schleim haut [6,28,29, 33,47,48,49,57,59].…”

unclassified

Der Einfluss einer glutenfreien Diät auf die Nährstoffresorption bei der einheimischen Sprue

Kasper¹

1967

Digestion

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Glucose and fructose absorption in idiopathic steatorrhoea.

Cited by 50 publications

References 9 publications

Unstirred layer and kinetics of electrogenic glucose absorption in the human jejunum in situ

Unstirred layer and kinetics of electrogenic glucose absorption in the human jejunum in situ

Impairment of glycine absorption by glucose and galactose in man

Der Einfluss einer glutenfreien Diät auf die Nährstoffresorption bei der einheimischen Sprue

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