Bioinorganic chemical studies on metal superoxide dismutases and their behavior in brain by the use of multielemental analysis.

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This study was undertaken in order to acquire better understanding of the biobehavior metal superoxide dismutases by the techniques of multitracer and instrumental neutron activation analysis. The followings were found.1) The radioactive multitracer technique was applied to a study on the uptake behavior of trace elements in normal C57BL/6N mice. Comparative uptake behavior of ^<46>Sc, ^<54>Mn, ^<59>Fe, ^<58>Co, ^<65>Zn, ^<75>Se, ^<83>Rb and ^<88>Zr tracers was examined among 11 organs (brain, cardiac muscle, lung, liver, spleen, pancreas, kidneys, bone, muscle, eyeballs and testes) and blood, and evaluated in terms of the "tissue uptake rate (the radioactivity percentage of injected dose per gram of tissue, %dose/g)". The multitracer technique revealed reliable data demonstrating characteristic uptake of the 8 trace elements, Sc, Mn, Fe, Co, Zn, Se, Rb and Zn by the brain and other organs, as well as the distinctive feature of the accumulation and retention of each element in the brai … More n. According to these results, it is evident that the metal ions examined in this work are easily transported into the brain, in addition, the high retention of Se, Rb, Mn and Zn in the brain during a fairly long time suggests active involvement of these elements in the brain function.2) Brain regional uptakes for ^<46>Sc, ^<54>Mn, ^<58>Co, ^<65>Zn, ^<75>Se, and ^<83>Rb in mice were examined using multitracer under deficient and excessive states of an essential trace elements, manganese, zinc or selenium. Zn-deficient and excessive states, and Se-deficient and excessive states influence the brain regional uptake behaviors of other trace elements except respective elements. On the other hand, in the mouse brain under Mn-deficient and excessive states, few interrelation between Mn and other elements was found from 0.4ppm to 300.4ppm. Multitracer technique was found to be very useful to screen the element-element interrelation in brain.3) Concentrations and uptake behavior of manganese (Mn), zinc (Zn) and selenium (Se) in mouse brain were studied by means of multitracer technique, neutron activation analysis and autoradiography. Comparative concentrations of Mn, Zn and Se and tracer uptake behavior of ^<54>Mn, ^<65>Zn and ^<75>Se were examined in the brain of 1-, 4-, 8-, 21- and 56-day-old mice, and evaluated in terms of brain concentration (part per million, ppm) and brain uptake rate (the radioactivity percentage of injected dose per gram of brain, %dose/g), respectively. As a result, the brain concentrations of Mn was increasing with growth, although those of Se and Zn were hardly changing. On the other hand, the uptakes of the 3 tracers by the brain of 1-day-old mice were much higher than those of other elder ones. Using radioactive ^<54>Mn as a single tracer, autoradiography was examined to known the Mn uptake regional distribution in the brain of 1-, 8- and 21-day-old mice, and observed higher regional uptake of Mn by the cerebral cortex, hippocampus, thalamus and hypothalamus in the young brain. Less