Absorption of Exogenous and Endogenous Biliary Copper in the Rat

Farrer, Paul A.; Mistilis, Steven P.

doi:10.1038/213291b0

Cited by 25 publications

(10 citation statements)

References 3 publications

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“…That histidine at a concentration of 100 mmol/l did not enhance absorption in this study may have been due to the alimentary secretions of the rat having a greater effect on the form of copper in the gut lumen than the small dose of histidine administered. Although the absorption of 64Cu from labelled human bile in vitro was markedly reduced when compared with the control series, similar results have previously been reported for rat bile (Owen, 1964;Farrer & Mistilis, 1967). However, the rat does not possess a gallbladder and it was therefore not entirely valid to extrapolate this finding to man.…”

Section: Discussionsupporting

confidence: 82%

Studies on the Nature of Complexes Formed by Copper with Human Alimentary Secretions and Their Influence on Copper Absorption in the Rat

Gollan

1975

Clinical Science

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1. Human gastrointestinal secretions formed soluble copper complexes when labelled in vitro with 64Cu. 2. Copper-binding substances of low molecular weight were demonstrated in the saliva, gastric juice and secretin-stimulated duodenal aspirate of nomal subjects by dialysis and gel-chromatography studies. 3. The nature of the copper complexes formed by secretions obtained from patients with Wilson's disease was similar to that oc complexes formed by secretions of normal subjects. 4. Bile contained a copper-binding fraction of high molecular weight which was more concentrated in gall-bladder than hepatic bile. Between pH 5 and pH 8, this component had a greater binding affinity EDTA at a concentration of 10 mmol/1. 5. Absorption of 64Cu from 64Cu-labelled saliva, gastric juice or L-histidine solution (100 mmol/1) administered intraduodenally into groups of rats was similar to that observed in a control series given [Cu]cupric acetate in sodium chloride solution. In contrast, the absorption of 64Cu from labelled hepatic and gall-bladder bile was significantly reduced. 6. The results suggest that dietary copper forms soluble complexes with the alimentary secretions and that these complexes influence absorption of the metal according to their molecular size. The net uptake of ingested copper from the gut lumen ms, low-molecular-weight ligands in the alimentary secretions and a macromolecular copper-binding complex of bile.

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Section: Discussionsupporting

confidence: 82%

Studies on the Nature of Complexes Formed by Copper with Human Alimentary Secretions and Their Influence on Copper Absorption in the Rat

Gollan

1975

Clinical Science

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“…Thus in the absence of dietary Cu supplements an estimated 0-16 mg Cu/day (0-46 of the amount secreted) was reabsorbed. This estimate can be compared with efficiencies of 0-21 + 0-04 reported for the apparent absorption of abomasally infused Cu in ruminating lambs (Suttle, 1975a), 0-10-0-22 for the apparent reabsorption of Cu from rat bile (Farrer & Mistilis, 1967) and 0-56 for the true absorption of Cu by humans (Strickland, Beckner & Mei-Ling Leu, 1972). The possibility of a feedback mechanism similar to those reported for Zn (Suttle, Lloyd-Davies & Field, 1982) and Fe (Underwood, 1977) whereby absorption was reduced cannot be ruled out as far as the long-term responses are concerned.…”

Section: Discussionmentioning

confidence: 93%

The long-term accumulation and depletion of copper in the liver of different breeds of sheep fed diets of differing copper content

Woolliams¹,

Suttle

Wiener³

et al. 1983

J. Agric. Sci.

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Changes in Cu concentration in the livers of adult Scottish Blackface (B), Welsh Mountain (W) and B x W ewes fed diets containing 4, 9, 17 and 29 mg Cu/kg D.M. were measured over a 28-week period. Measurement continued during two further periods of 18 weeks when first all sheep were fed the diet containing 4 mg Cu/kg D.M. and finally, when 4 mg Mo/kg D.M. was added to this diet.During the first period the increase on all diets was least in B ewes and, apart from the 4 mg Cu/kg D.M. diet, greatest in W ewes; this difference increased as the Cu in the diet increased. The rate of increase for all ewes diminished towards the end of the period. All breed types retained proportionately less Cu in their livers as the Cu in the diet increased; at one extreme B ewes fed 17 or 29 mg Cu/kg D.M. retained equal amounts.When during the second period all sheep were fed the 4 mg Cu/kg D.M. diet the Cu concentration in their livers decreased, the rate of decrease being greatest for ewes whose mean concentration in the liver was highest, but at similar concentrations the decrease was greater in B than W ewes. During the final period the decrease was faster and was again associated with the mean Cu concentration, but the decrease was not significantly affected by breed.Throughout the trial, W ewes had the highest concentration of Cu in their plasma, whilst B ewes and ewes fed the 4 mg Cu/kg D.M. diet throughout had the lowest concentrations both in plasma and in their kidneys at slaughter.The results show that breeds differ in their ability to retain Cu from the diet in their livers. The magnitude of these differences depends on the intake of Cu and Mo from the diet and is affected by the concentration of Cu in the liver. Breed differences in the absorption and endogenous loss of Cu are suggested.

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“…Previous studies by Farrer & Mistilis (1967) using bile labelled in vivo with 64Cu from rats showed that an average of 51% of the radionuclide diffused into 0.15 M-NaCI at pH 6.5-6.9. With similarly labelled rat bile, Frommer (1971) observed that approx.…”

Section: Discussionmentioning

confidence: 98%

Studies on the Nature and Excretion of Biliary Copper in Man

Gollan

Deller

1973

Clinical Science

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S U M M A R Y 1. Gall-bladder bile was obtained at cholecystectomy from seven patients who had been given [64Cu]cupric acetate intravenously.2. Studies using dialysis and Sephadex gel filtration indicated that most of the 64Cu in the bile was in a heat-stable complex of molecular weight exceeding 50 000. The remaining biliary 64Cu was in a low-molecular-weight component.3. Above pH 4, 64Cu could not readily be removed from the macromolecular complex either by excess carrier copper ions, by D-penicillamine or by EDTA.4. Absorption of 64Cu from 64Cu-labelled bile injected intraduodenally into rats was significantly less than from [64Cu]cupric acetate similarly injected.5. These observations suggest that limitation of an entero-hepatic circulation of copper by a biliary macromolecule which differs from caeruloplasmin, may be a significant factor in copper homeostasis in man.

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Absorption of Exogenous and Endogenous Biliary Copper in the Rat

Cited by 25 publications

References 3 publications

Studies on the Nature of Complexes Formed by Copper with Human Alimentary Secretions and Their Influence on Copper Absorption in the Rat

Studies on the Nature of Complexes Formed by Copper with Human Alimentary Secretions and Their Influence on Copper Absorption in the Rat

The long-term accumulation and depletion of copper in the liver of different breeds of sheep fed diets of differing copper content

Studies on the Nature and Excretion of Biliary Copper in Man

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