Profiles of ⁶⁷Cu in blood, bile, urine and faeces from ⁶⁷Cu-primed lambs: effect of ⁹⁹Mo-labelled tetrathiomolybdate on the metabolism of recently stored tissue ⁶⁷Cu

Abstract

1. The relative importance of excretory routes in the removal of recently stored 67Cu following tetrathiomolybdate (TTM) administration was studied. Lambs fed on either 5 mg Cu/kg dry matter (DM) or 35 mg Cu/kg DM, were primed intravenously (iv) with 87Cu and challenged 27 h later with gsMo-labelled TTM given either iv or intraduodenally (id). The profiles of "Cu and esMo and of Cu and Mo in blood, bile, urine and faeces were measured.2. Level of dietary Cu and route of administration of "Mo-TTM affected the amplitude of blood, bile and urine profiles of 67Cu and stable Cu, but not the pattern of the responses observed.3. The present study describes for the first time increased excretion of endogenous 87Cu through gastrointestinal secretions other than bile due to TTM administration.4. Administration of TTM resulted in the immediate release of 67Cu from storage compartments in the body into the blood circulation. Changes in stable Cu levels in blood, bile, urine and faeces, and gut and systemic effects were evident, Biliary and urinary Cu excretion due to TTM was rapid and maximal within 24 h of injection.5. Administration of "Cu iv resulted in the immediate excretion of "Cu in bile in a pulsatile, constant pattern. A similar pattern of 87Cu excretion into bile in synchrony with that of OOMo was observed after esMo-labelled I T M administration.6. The similar pattern of biliary 67Cu excretion observed after injection of 'lCu and after injection of geMolabelled TTM 27 h later is discussed in relation to the times required to process the Cu through different hepatic pathways for excretion in bile.Molybdenum and sulphur-induced copper deficiency in ruminants (Mills, 1985) is probably mediated through the thiomolybdates (TM) (MoO,S,., where n is 0-3). Di-and trithiomolybdates predominate in plasma of sheep given either normal or slightly elevated levels of Mo . 1981 a). Most of the increased Cu in plasma is present in an unidentified trichloroacetic acid (TCA)-insoluble form, the source

Effects of dietary copper, molybdenum and sulfur on biliary copper and zinc excretion in Simmental and Angus cattle

“…This is the first study that has examined the effect of dietary Mo and S on biliary Cu excretion in ruminants. Preliminary findings were previously reported (Gooneratne et al 1987;1988b).…”

Profiles of 67Cu in blood, bile, urine and faeces from 67Cu-primed lambs: effect of 99Mo-labelled tetrathiomolybdate on the metabolism of 67Cu after long-term storage

“…Experimental animals Four female lambs drawn from a pool of eight cross-bred female lambs (17-22 kg) were used in the present study. The procedures for housing, feeding, bile duct and duodenal cannulation techniques, period of time allowed for recovery from surgery, bile flow stabilization period and sampling schedule to determine baseline values of Cu in plasma, bile, urine and faeces before radiotracer studies, have been reported (Gooneratne et al 1989). The lambs received either 5.1 mg Cu/kg (lamb nos.…”

“…carried out to evaluate the fate of Cu in the long-term Cu storage compartment, and to determine the effectiveness of TTM in the removal of Cu from this compartment. Systemic effects of TTM and relative efficiencies of body Cu removal via the different excretory pathways were examined, with special emphasis on deviations in mechanisms of biliary Cu excretion compared with the mechanisms proposed for bile Cu excretion from the shortterm Cu storage compartment (Gooneratne et al 1989).…”

Review of Copper Deficiency and Metabolism in Ruminants

“…Cytochrome oxidase activity of the intestinal epithelial cells was reduced indicating local interference in the^availability of Cu to these cells. Since S'-may be generated from TM, it seems possible that S'-may have inhibited cytochrome oxidase directly (Nicholls 1975 (trans-biliary, transhepatocellular and hepatolysosomal) were the same either after o'Cu or after TM4 administration (Gooneratne et al 1989c). However, during removal of Cu from a long-term storage compartment, the transhepatocellular pathway appeared absent, while transbiliary and hepatolysosomal pathways were still operative (Gooneratne et al 1989d).…”