シロネズミに投与したビタミンB_<12>の代謝回転と腸管との関係

概要

論文の詳細を見る
Although the speed of B_<12> turnover in man has been estimated to be slow, little is known about the route of B_<12> loss. The present study was designed to determine the speed of B_<12> turnover and the routes of B_<12> loss in rats, using a specially designed whole body counter, and the role of small intestine in B_<12> loss. It was found that the major portion of subcutaneously injected ^<57>Co-B_<12> was lost in feces and the biological half life of B_<12> after settlement in tissues was about 32 days, with a fair correlation between decrease of radioactivity from body and increase in cumulative fecal excretion. Excretion into intestinal fluid as collected from the end of duodenum was smaller than that from the ileal end, and the total radioactivity present at one time in mucosa was not large enough to account for fecal excretion. It is suggested that there is a constant uptake of B_<12> and loss of B_<12> by the intestinal mucosa. Intermittent administration of sublethal doses of x-radiation resulted in retardation of decrease in mucosal radioactivity, and preparation of large emptying intestinal loop demonstrated accelerated turnover of mucosal B_<12> in the bypassed segment.
日本ビタミン学会の論文
1971-08-25