マンガンイオンのラット体内分布と原子価状態

抄録

Although the essential roles of manganese ion (Mn) and requirement of its homeostasis have been studied in various biological systems, little is known about how Mn actually plays physiological roles. Our interests are focused on the determination of the redox passway of Mn through which Mn is transffered to an appropriate location for its function.

We determined the tissue and subcellular distributions of Mn (II), determined by ESR ( electron spin resonance), and of total Mn, determined by neutron activation analysis combined with chemical separation, differentiating two species of Mn in rats with and without MnCl₂-treatment.

In controls, total Mn content was high in the thyroid, hypophysis, adrenal, pancreas, liver and kidney, but Mn(II) contents of these tissues were low. In animals treated with MnCl₂, the total Mn content of all tissues increased, but the Mn(II) content remained low. In subcellular distribution, the total Mn content was high in nuclear and mitochondrial fractions of liver and kidney, and in the microsomal and supernatant fractions of the pancreas. The ratio of Mn(II) to total Mn was relatively high in microsomes of the liver and kidney of control rats, and in the nuclear fraction of pancreas of Mn-treated rats.

Partially purified liver nuclei and mitochondria were found to contain higher levels of Mn than the crude compartments, indicating that Mn is tightly bound in each cellular compartment.