Erythrocyte zinc

PbB concentrations reflect the absorbed dose of lead. However, the interpretation of PbB data depends on a knowledge of the past history of exposure to lead. This is because in the body, bone constitutes the major lead sink and this results in lead having a long body half-life. Thus, in the absence of intense exposure to lead for a considerable period up to its body half-life, the PbB concentrations reflect recent lead exposures. However, if intermittent exposure to lead is occurring in several distinct environments, the PbB concentration reflects both recent and past exposures to lead. Thus, biological effects for populations with the same PbB concentrations may not be the same since different exposure times scales may be involved. This is the reason why free erythrocyte protoporphyrin (FEP) and erythrocyte zinc protoporphyrin (ZPP) have been used as additional biological markers since their elevation is more related to chronic lead exposure than acute lead exposure (see Section 2.7). 

Odone P, Castoldi MR, Guercilena S, et al. 1979. Erythrocyte zinc protoporphyrin as an indicator of the biological effect of lead in adults and children. In International Conference on Management and Control of Heavy Metals in the Environment, London, United Kingdom, September. Edinburgh, UK CEP Consultants, Ltd., 66-69. 

Zinc protoporphyrin IX is a normal metabolite that is formed in trace amounts during haem biosynthesis. However, in iron deficiency or in impaired iron utilization, zinc becomes an alternative substrate for ferrochelatase and elevated levels of zinc protoporphyrin IX, which has a known low affinity for oxygen, are formed. This zinc-for-iron substitution is one of the first biochemical responses to iron depletion, and erythrocyte zinc protoporphyrin is therefore a very sensitive index of bone-marrow iron status (Labbe et ah, 1999). In addition, zinc protoporphyrin may regulate haem catabolism by acting as a competitive inhibitor of haem oxygenase, the key enzyme of the haem degradation pathway. However, it has been reported... 

Changes in the erythrocyte zinc concentration were slow to appear as expected on the other hand, changes In the leukocyte zinc concentration appeared more sensitive to changes In zinc intake. Urinary excretion of zinc decreased as a result of dietary zinc restriction, suggesting that renal conservation of zinc may be Important for the homeostatic control mechanism in man. Thus, measuring zinc concentration in a 24-h urine test may be of additional help in diagnosing zinc deficiency provided cirrhosis of the liver, sickle cell disease, and chronic renal diseases are ruled out. These conditions are known to have hyperzlncuria and associated zinc deficiency. 

Kosman DJ, Henkin Rl. 1981. Erythrocyte zinc in patients with taste and smell dysfunction [Letter]. 

Determination of Erythrocyte Zinc Protoporphyrin Methodological Problems... 

Elevated erythrocyte zinc protoporphyrin indicates iron-deficient erythropoiesis. Protoporphyrin concentrations may also be elevated by inflammation and lead exposure. 

Zinc. The 2—3 g of zinc in the human body are widely distributed in every tissue and tissue duid (90—92). About 90 wt % is in muscle and bone unusually high concentrations are in the choroid of the eye and in the prostate gland (93). Almost all of the zinc in the blood is associated with carbonic anhydrase in the erythrocytes (94). Zinc is concentrated in nucleic acids (90), and found in the nuclear, mitochondrial, and supernatant fractions of all cells. 

Water soluble protein with a relative molecular mass of ca. 32600, which particularly contains copper and zinc bound like chelate (ca. 4 gram atoms) and has superoxide-dismutase-activity. It is isolated from bovine liver or from hemolyzed, plasma free erythrocytes obtained from bovine blood. Purification by manyfold fractionated precipitation and solvolyse methods and definitive separation of the residual foreign proteins by denaturizing heating of the orgotein concentrate in buffer solution to ca. 65-70 C and gel filtration and/or dialysis. 

Zinc protoporphyrin in blood After 1 month exposure 2 50 pg/100 ml erythrocytes or lOOpg/IOOmI blood B... 

Inhibition of ferrochelatase in the heme pathway causes accumulation of protoporphyrin in erythrocytes (CDC 1985). Most protoporphyrin in erythrocytes (about 90%) exists as zinc protoporphyrin (ZnPP). This fraction is preferentially measured by hematofluorometers. Extraction methods measure all the protoporphyrin present, but strip the zinc from the ZnPP during the extraction process. For this reason,... 

Chisolm JJ Jr, Brown DH. 1979. Micromethod for zinc protoporphyrin in erythrocytes Including new data on the absorptivity of zinc protoporphyrin and new observation in neonates and sickle cell disease. Biochem Med 22 214-237. 

Davis JR, Avram MJ. 1978. A comparison of the stimulatory effects of cadmium and zinc on normal and lead-inhibited human erythrocytic delta-aminolevulinic acid dehydratase activity in vitro. Toxicol Appl Pharmacol 44 181 -190. 

Thomasino JA, Zuroweste E, Brooks SM, et al. 1977. Lead, zinc and erythrocyte delta-aminolevulinic acid dehydratase Relationships in lead toxicity. Arch Environ Health 32 244-247. 

The first recognition of a role for zinc in biochemistry was the discovery inl939 that it was an essential component of carbonic anhydrase, a key enzyme in erythrocytes that catalyses the formation of bicarbonate ... 

J.S. Valentine, M.W. Pantoliano, PJ. Mcdonnell, A.R. Burger, and S.J. Lippard, pH-dependent migration of copper(II) to the vacant zinc-binding site of zinc-free bovine erythrocyte superoxide dismutase. Proc. Natl. Acad. Sci. U.S.A. 76, 4245-4249 (1979). 

J.V. Bannister, W.H. Bannister, and E.J. Wood, Bovine erythrocyte cupro-zinc protein. 1. Isolation and general characterization. Fur. J. Biochem. 18, 178-186 (1971). 

J.A. Fee and R.G. Briggs, Reconstitution of bovine erythrocyte superoxide dismutase. V. Preparation and properties of derivatives in which both zinc and copper sites contain copper. Biochim. Biophy. Acta. 400, 439 150 (1975). 

Iron-, copper-, and zinc complexes of rutin, dihydroquercetin, and green tea epicatechins were found to be much more efficient inhibitors than parent flavonoids of toxic effects of chrysotile asbestos fibers on peritoneal macrophages and erythrocytes [168], It was proposed that in this case the enhanced activity of metal-flavonoid complexes was increased by the absorption on chrysotile fibers. 

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