Contents and uptake rates of Mn, Fe, Co, Zn, and Se in Se-deficient rat liver cell fractions.

The contents of manganese (Mn), iron (Fe), cobalt (Co), zinc (Zn), and selenium (Se) in nuclear (NU), mitochondrial (MT), microsomal (MC), and cytosolic (CS) fractions of liver homogenates of normal and selenium-deficient (SeD) rats were determined by instrumental neutron activation analysis (INAA). The uptake rates of these elements in the liver cell fractions of both groups of rats were determined by multitracer analysis (MTA). The results indicated that Se-deficiency caused a significant increase in the content of Fe in the MC fractions. The MTA showed that the uptake rate of Fe was highest in the MC fraction, and that the uptake rate in the fraction was similar between the SeD and normal rats.

Comparative uptake behavior of trace elements in adult and suckling rat lens.

The multitracer technique was applied to the determination of the uptake of trace elements in the lenses of adult and suckling rats to investigate the transport mechanisms of trace elements during developmental maturation. Be, Sc, V, Mn, Fe, Co, Zn, As, Se, Rb, Sr, Y, Zr, Ru and Rh accumulate in adult and suckling rat lenses. The rates of uptake of trace elements differ among each species and also differ between adult and suckling rat lenses. The uptakes of Fe and Sr are greater in adult rat lenses, while the uptakes of Se and Rb are greater in suckling rat lenses. High concentrations of Zn are transported into the lenses of both adult and suckling rats in comparison with other elements, and the content of Zn in suckling rat lens is higher than in adult lens. The present study suggests that different mechanisms depending on the stage of development act to transport trace elements into lenses.

Binding properties of various metals to blood components and serum proteins: a multitracer study.

The binding affinity of various trace elements to blood components and the pH-dependence of the binding affinity of the elements to serum proteins were examined using the radioactive multitracer technique. The binding affinity of 13 elements (Be, V, Mn, Zn, Se, Rb, Sr, Ce, Eu, Gd, Tm, Yb, and Lu) was simultaneously determined by gamma-ray spectrometry. The blood drawn from rats was separated into plasma, corpuscles, and erythrocyte ghosts. It was found that Be, Sr, Mn, and Zn bind highly to the plasma proteins. V and Se were highly bound to the corpuscles, and Se to the erythrocyte ghosts as well. Similar binding percentages of rare earth elements (Ce, Eu, Gd, Tm, Yb, and Lu) were found for each of the blood components, with the highest percentages being observed for plasma proteins. Albumin, beta-globulin, gamma-globulin, apotransferrin, and holotransferrin were examined in the study on the affinity of individual serum proteins. The pH dependence of the affinity of metal ions to the serum proteins in the pH range of 6.4-8.5 was examined using ultrafiltration and gamma-ray spectrometry. Each element showed a characteristic binding affinity to each serum protein, depending on pH. The results are discussed in terms of the chelating ability of metal ions and the nature of the serum proteins.

Study on the distribution of radioactive trace elements in vitamin D-overloaded rats using the multitracer technique.

The uptake and distribution of radioisotopes of beryllium, calcium, scandium, vanadium, chromium, manganese, iron, cobalt, nickel, zinc, gallium, arsenic, strontium and barium in vitamin D (VD)-overloaded rats were investigated and compared with those in control rats, using the multitracer technique. Each element revealed its characteristic distribution among various organs in control and VD-overloaded rats. For some elements, such as cobalt and chromium, the distribution patterns in them were significantly different. These results are discussed in terms of the metabolism of the elements in rats.

The use of a multitracer technique for the studies of the uptake and retention of trace elements in rats.

The uptake by, and distribution and retention of radioactive isotopes in various organs of Wistar rats were examined using the multitracer technique. A hydrocholoric acid solution (pH 3) of a carrier-free radioactive multitracer was prepared from gold foil irradiated with a 14N beam of 135 MeV nucleon. The solution was administered orally to 12 7-week-old male rats. Urine and faeces were collected and each group of three rats was killed at 1, 2, 3 or 6 days after administration. The percentage of administered dose of the 17 elements, Mn, Co, Zn, As, Rb, Sr, Y, Eu, Gd, Er, Tm, Yb, Lu, W, Re, Ir and Pt in the organs blood and excreta were determined using gamma-ray spectrometry. Each element revealed its characteristic distribution among the different organs, including the blood. These results are discussed and compared with those of single-tracer experiments, and the advantages of the multitracer technique are presented.

Multitracer study on uptake and excretion of trace elements in rats.

The multitracer technique was first applied to the investigation of the uptake and excretion behaviour of trace elements in rats. A multitracer solution, prepared by irradiation of a gold target with a 14N-beam from the RIKEN Ring Cyclotron, was orally administered to male Wistar rats. The uptake and excretion rates of 23 elements, Be, Mn, Co, Zn, As, Rb, Sr, Y, Zr, Ce, Pm, Eu, Gd, Tb, Er, Tm, Yb, Lu, Hf, W, Re, Ir and Pt, were simultaneously determined under strictly identical experimental conditions. For some of the elements, the results obtained were consistent with previous reports on uptake and excretion of the elements in animals. For the other elements, unique behaviour was revealed for the first time as described in the present work. These results show that the multitracer technique has excellent reliability and versatility for a comparative study of the uptake and excretion of many different elements in animals.