低ミネラル・高アルミニウム食によるラット軟部組織（ことに中枢神経組織）と骨でのマグネシウム，カルシウム分布

DISTRIBUTION OF CALCIUM AND MAGNESIUM IN SOFT TISSUES, ESPECIALLY IN CENTRAL NERVOUS SYSTEM, AND BONE OF RATS FED WITH LOW CALCIUM-MAGNESIUM WITH OR WITHOUT ALUMINUM LOADING DIETS

　中枢神経組織（CNS）の変性にカルシウム（Ca），マグネシゥム（Mg），アルミニゥム（Al）が関与することが指摘されている。この研究は低Ca・Mg，高Al負荷によりCNSを初めとする軟部組織，皮質骨および骨梁骨のMg，Ca分布について検討したものである。28匹のラットを4群に分け，A群：ラット標確食・B群：低Ca食，C群：低Ca・Mg食，D群：低Ca・Mg十高A1食，で90日間飼育した。血清CaはA群＞B群＞D群＞C群の順序を示し，血清Mgは食餌内容を反映して，A，B群に比べ，C，D群で低下した。前頭葉のCa量はB群に比べC群で増加し，Alを負荷したD群でさらに上昇した。CNSの他の部位でもこの傾向を示した。またC，D群の心，肝，腹部大動脈，腎でもA，B群に比べCa量は上昇した。また骨のCa量はA群に比べB，C，D群で有意に低下し，その傾向は骨梁骨で明瞭であった。骨Mg量は・A群＞B群＞C群＞D群の順序で，骨梁骨および皮質骨ともに低下した。以上より，アンバランスなミネラル食により誘発された骨のmineralizationの不安定な状態では，CNSを含む軟部組織の細胞賦活を維持するために，ミネラル欠乏食で飼育されたラットの骨からこれらの組織へCa，Mgが動員され，その結果，CNS中にはCaが異常に沈着し，Mgはほぼ正常の濃度に維持されると考えられる。

Current epidemiological investigations in the Western Pacific area have suggested that the environmental factors contribute to the patho-genetic process of amyotrophic lateral sclerosis (ALS). The condition of unbalanced minerals found in soil and drinking water of ALS foci with low content of Ca and Mg plus high con-tent of Al was experimentally mimicked in this study using rats. In the groups fed with low calcium diet, low Ca-Mg diet and low Ca-Mg plus high Al diet, serum calcium levels werelower than those in the group fed with standard diet. Also serum Mg levels were lower in the groups fed with low Ca-Mg diet and low Ca-Mg plus high Al diet than in the group fed with standard diet and low Ca diet. However, there was no significant difference in Mg content of the central nervous system (CNS) tissues of groups with unbalanced and standard diets except for that in spinal cord of rats fed with low Ca-Mg plus high Al diet, determined by inductively coupled plasma emission spectrometry. On the other hand, Ca content of CNS showed higher values in the unbalanced diet groups, especially in spinal cord of the low Ca-Mg plus high Al diet group, than those in the standard diet group. And Ca content in heart, liver, kidney and abdominal aorta of rats fed with both low Ca-Mg diet and low Ca-Mg plus high Al diet increased that those of standard and low Ca diet groups. Ca content in muscle of all three unbalanced diet groups was significantlyhigher compared to those of standard diet group. Mg content of heart and muscle was remarkably diminished in low Ca-Mg plus high Al diet gro-up, but Mg content in soft tissues of rats fed with low Ca-Mg diet alone was not altered. Ca and Mg content in lumbar spine and cortical bone showed higher values in a standard diet group than those in the unbalanced diet groups i. e. low Ca diet group, low Ca-Mg diet group, and low Ca-Mg plus high Al diet group. It seems that under the condition of the derangment of min-eralization in bone induced by unbalanced mineral diets, Ca and Mg may be allowed to mobilize from bone of rats fed with mineral deficient diets and to keep its content in soft tissues including the CNS tissues for the utilization of their vital activity, thereby resulting in deposition of Ca and maintenance of almost normal value of Mg in CNS tissues.