Six groups of Wistar rats were used to demonstrate effects of magnesium deficiencies on thiamine metabolism. Group I was fed both a thiamine and magnesium deficient diet, Group II a thiamine deficient and magnesium sufficient diet, Group III a thiamine adequate and magnesium deficient diet, Group IV a thiamine adequate and magnesium sufficient diet (control), Group V an excess thiamine and magnesium deficient diet and Group VI an excess thiamine and magnesium sufficient diet. Animals were sacrificed after four weeks and magnesium, thiamine and transketolase activities were determined in various tissues.
Magnesium concentration in blood cells, plasma and bone decreased markedly in the thiamine supplemented-magnesium deficient groups (Group III and V) compared to that in the group deficient in both thiamine and magnesium (Group I). This finding suggests that the thiamine deficiency inhibited utilization of magnesium. Thiamine content of the sciatic nerve, liver and kidney of the magnesium deficient rats were lower than in the magnesium sufficient rats. This suggests that magnesium plays a considerable role in the maintenance of thiamine in tissues. No decrease of thiamine was detected in the central nervous system of magnesium deficient rats. Tissue transketolase activity decreased markedly in thiamine deficient and thiamine-magnesium deficient rats (Group I and II). Addition of thiamine pyrophosphate to tissue homogenates of thiamine deficient rats (Group II) resulted in recovery of transketolase activity, however this phenomenon did not occur when rats were also deficient in magnesium (Group I).
