Cadmium liver content

Metallothioneins are a group of small proteins (about 6.5 kDa), found in the cytosol of cells, particularly of liver, kidney, and intestine. They have a high content of cysteine and can bind copper, zinc, cadmium, and mercury. The SH groups of cysteine are involved in binding the metals. Acute intake (eg, by injection) of copper and of certain other metals increases the amount (induction) of these proteins in tissues, as does administration of certain hormones or cytokines. These proteins may function to store the above metals in a nontoxic form and are involved in their overall metaboHsm in the body. Sequestration of copper also diminishes the amount of this metal available to generate free radicals. 

BaP alone produced glycogen depletion in liver cadmium alone caused hepatic perivascular fibrosis. Mixture produced complete disorganization of the hepatic parenchyma, including nuclear degeneration higher increase in EROD activity (by 19-fold), BaP hydroxylase activity (by 71-fold), and cytochrome P-450 microsomal content by 2-fold... 

One example of the use of semiempirical methodology is provided in an article detailing a molecular-dynamics simulation of the beta domain of metallothionein with a semiempirical treatment of the metal core.73 The beta domain of rat liver metallothionein-2 contains three-metal centers. In this study, three molecular variants with different metal contents—(1) three cadmium ions, (2) three zinc ions, and (3) one cadmium ion and two zinc ions—were investigated using a conventional molecular dynamics simulation, as well as a simulation with a semiempirical quantum chemical description (MNDO and MNDO/d) of the metal core embedded in a classical environment. For the purely classical simulations, the standard GROMOS96 force-field parameters were used, and parameters were estimated for cadmium. The results of both kinds of simulations were compared to each other... 

Although trace element abnormalities occur in chronic renal failure, few symptoms have been attributed to them in nondialyzed patients. In dialysis patients these disturbances appear to be qualitatively similar but more severe (T7). They have been extensively reviewed by Alfrey (A5). Total body zinc (except in erythrocytes), strontium, aluminum, and tin are generally increased, whereas total body rubidium is decreased. Iron stores tend to be increased in the spleen and liver in dialyzed patients, especially after ferrous sulfate therapy. Copper is increased in lung tissue and decreased in heart tissue and erythrocytes. Molybdenum and cadmium are decreased in renal tissue but increased in liver tissue of dialyzed and nondialyzed patients. Total body zinc content is significantly increased (A5), but hypozincemia, frequently observed in dialysis patients, has been blamed for taste impairment and impotence and there is conflicting evidence on whether zinc repletion corrects these abnormalities (K4, Ml2). Nickel is also increased in the serum of uremic patients, but this does not appear to be associated with a corresponding increase in tissues (S5). It cannot be concluded that trace element retention in renal failure is of no clinical importance, as shown by the problem of aluminum intoxication, to be discussed later. In addition, trace elements such as rubidium and bromine, which are rapidly depleted in uremic patients on maintenance dialysis (A5), may prove to be essential in normal metabolism. Thus the clinical importance of these element alterations remains unclear. 

Tiran, B., Karpf, E., Tiran, A., 1995. Age dependency of selenium and cadmium content in human liver, kidney, and thyroid. Arch. Environ. Health 50, 242-246. 

Ra agopalan et al. ( ) have demonstrated that administration of AuCl., a gold(IIiy complex, to rats results in increased levels of liver zinc metallothionein (the gold content of the cytosol fractions were not measured). However, gold(III) is much more toxic than gold(I)(D and the effect may be a non-specific stress induction of MT, similar to that produced by CC1-, bacterial infections, etc. (29-31) Although the distinction may seem to be semantic, the extent of MT-biosynthesis induced by cadmium versus gold and the consequences for the biochemistry of the metals are quantitatively and qualitatively different. 

Asokan P, Tandon SK (1981) Effect of cadmium on hepatic metallothionein level in early development of the rat. Environ. Res 24 201-206 Bakka A, Webb M (1981) Metabolism of zinc and copper in the neonate changes in concentrations and contents of thionein-bound Zn and Cu with age in the livers of the newborn of various mammalian species. Biochem. Pharmacol 30 721-725 Bell JU (1980) Induction of hepatic metallothionein in the immature rat following administration of cadmium. Toxicol. Appl Pharmacol 54 148-155 Barltrop D, Khoo HE (1979) The influence of dietary minerals and fat on the absorption of lead. The Sci. Total Environ 6 265-273 Bushnell PJ, DeLuca HF (1981) Lactose facilitates the intestinal absorption of lead in weanling rats. Science 211 61-63... 

Riordan JR, Richards V (1980) Human fetal liver contains both copper-rich forms of metallothionein. J Biol Chem 255 5380-5383 Robbins AH, McRae DE, Williamson M, Collett SA, Xuong NH, Furey WF, Wang BC, Stout CD (1991) Refined crystal structure of Cd.Zn metallothionein at 2.0 A resolution. J Mol Biol 221 1269-1293 Rugstad HE, Norseth T (1975) Cadmium resistance and content of cadmium-binding protein in cultured human cells. Nature 257 136 Ryden L, Deutsch HF (1978) Preparation and properties of the major copperbinding component in human fetal liver. J Biol Chem 253 519-524 Sato M, Bremner I (1993) Oxygen free radicals and metallothionein. Free Radic Biol Med 14 325-337... 

Contamination of the environment by the toxic elements increases their content in the organs and tissues of animals. Toxic elements enter the bodies of animals in particular by the oral route via consumed food. In human nutrition, the concentration of these elements in muscle and viscera of animals (farm as well as wild animals) is the most important factor. The content of lead and cadmium in the liver and kidneys of wild animals indicates the load of the contaminated animal food and habitat pollution level in which an animal lives. Under normal conditions, the content of lead and cadmium in meat is very low (thousandths of mg/kg), in contrast to the concentration in the kidney and Hver, which are sometimes up to 2-3 orders of magnitude higher. In these organs, lead and cadmium accumulate signihcantly. 

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