Effect of dietary Mo on Cu metabolism. Evidence for the involvement of Mo in abnormal binding of Cu to plasma proteins

Smith, B.S.W.; Wrigth, H.

doi:10.1016/0009-8981(75)90279-x

Cited by 45 publications

(4 citation statements)

References 18 publications

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“…While liver biopsies were not attempted, and thus the hepatic copper status of the animals could not be assessed, there was no evidence that copper metabolism was perturbed by the supplementation. The animals remained healthy and, significantly, the characteristic increase in TCA-insoluble copper or albumin-bound copper described in sheep (Smith and Wright 1975; Lamand el a/ 1980) and cattle (El-Gallad ef a1 1983; Hynes er a1 1985) was absent.…”

Section: Discussionmentioning

confidence: 89%

Dietary molybdenum as a putative copper antagonist in the horse

Strickland

Smith

Woods

et al. 1987

Equine Veterinary Journal

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Summary Four horses were stabled and fed a diet of hay ad libitum, and 2 kg oats per animal per day, for a month. The basic diet was then supplemented with molybdenum, at a rate of 20 mg/kg dry matter for 4.5 months. For one month of this period the diet was supplemented also with sulphur at a rate of 1.2 g/kg dry matter. Analyses of jugular blood samples, obtained at intervals varying between two and 20 days, showed no evidence of a decline in total plasma copper or of an increased proportion of trichloroacetic acid (TCA) insoluble copper in plasma over this period. In separate studies, two other horses were given “molybdenum (molybdate, 20 to 28 mg Mo, 4 mCi per animal) per os, initially while being fed the basic diet and later while maintained on the molybdenum supplemented diet. 99Molybdenum appeared rapidly in plasma, but the radioactivity was then quickly cleared (half‐life 7 to 10 h). The 99molybdenum present was identified as (99Mo)‐molybdate. There was no evidence of the persistent, protein‐bound (99Mo)thiomolybdates which appear in ruminants. These studies indicate that increased dietary molybdenum is unlikely to interfere with copper metabolism in horses.

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Section: Discussionmentioning

confidence: 89%

Dietary molybdenum as a putative copper antagonist in the horse

Strickland

Smith

Woods

et al. 1987

Equine Veterinary Journal

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“…Studies of the distribution of Cu in the plasma of Mo-supplemented sheep and guinea-pigs have shown that Cp and :DR Cu do not account for all of the plasma Cu (Suttle & Field, 1968;Smith et al 1968) The occurrence of a non-Cp and non-albumin Cu has been demonstrated (Bremner dr Young, 1978). This residual Cu fraction precipitated by TCA contains both Mo (Smith & Wright, 19756) and protein (Smith & Wright, 1974, 1975a. The origin and metabolic significance of this fraction is yet to be established.…”

Section: Discussionmentioning

confidence: 99%

An investigation of the effects of intravenous administration of thiomolybdate on copper metabolism in chronic Cu-poisoned sheep

1981

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1. Fourteen sheep were doscd repeatedly with a solution of copper sulphate (2 g/l) in order to induce chronic copper poisoning and four similar undosed animals acted as controls.2. Thiomolybdate (TM) was intravenously administered to all control sheep and to all except two of the test sheep. A variety of biochemiclil factors were studied before and after injections of TM.3. The direct-reacting Cu. Hhole-blood Cu and plasma Cu concentrations were elevated in animals given TM injections and at the 'haemolyiic crisis' of untreated chronic Cu-poisoned animals. But most of the increased Cu observed on injecting TM was insoluble in trichloroacetic acid (TCA) and did not enter erythrocytes. The results indicate that uptake of Cu by erythrocytes is essential for haemolysis to occur and that for this to happen the Cu must be in a direct reacting, TCA-soluble form. 4. Increased amounts of Cu were excreted in the urine at haemolysis and at the commencement of TM injections.High levels of direct-reacting Cu were found in plasma at these times. 5.Marked changes were not found in caeruloplasmin activity, packed cell volume or the osmotic fragility of erythrocytes except at haemol!/sis. TM injections did not alter these factors in any of the sheep studied.

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“…8 High concentrations of Mo in the diet in the presence of adequate sulphur can result in the appearance of Cu -thiomolybdate complexes in plasma. These complexes, which are insoluble in TCA, 19,20 probably accounted for the difference between total and TCA-soluble plasma Cu in both of our flocks (Tables 3 and 4) and could be expected to reduce the amount of biologically available Cu in circulation.…”

Section: Discussionmentioning

confidence: 93%