Abstract
Riboflavin deficiency has been of endemic occurrence in Miyoshi village, a farm district in Aomori Prefecture, where peat deposits were distributed widely and found superficially beneath the earth. The well-water in this area showed higher content in Mg, Mn, Na, Ca, Cl and phenol than city-water. The present work was attempted to investigate the influence of well-water upon riboflavin metabolism of rats. After feeding on standard diet prepared by using city-water, the rats were divided into 3 groups, according to the kind of water which was used for preparing food and for drinking. Group 1 (city-water group), group 2 (well water group) and group 3 ("Mn-water" group). "Mn-water" was the city water into which MnCl_2 was added in the same concentration as contained in the well-water, amounting to 10 ppm Mn. Each of water was given in an amount of 20ml per day per rat. In groups 2 and 3 as compared with group 1,marked decrease in riboflavin concentration was found in blood, liver and kidney, which were examined on the 6th month after giving well-water or Mn-water. Urinary output of riboflavin was increased temporarily over a period from 10 to 20 days after giving well-water or "Mn-water", and thereafter it decreased gradually, simultaneonsly with the decrease of riboflavin in stools. These results was explained by the experimental findings that well-water, especially Mn^<++> in it, activated nucleotide pyrophosphatase (FAD-FMN) and drived out riboflavin from the body into urine on one hand, and depressed intestinal synthesis of riboflavin on the other hand.
