The absorption of radioactive sulphur-labelled thiamine hydrochloride in control subjects and in patients with intestinal malabsorption

Abstract

(1) A method is described for investigating vitamin B1 absorption in man by measuring the urinary radioactivity during the 24 hours following an oral dose of radioactive 35S- thiamine which is given along with a parentergl injection of non -radioactive thiamine hydrochloride. (2) Analysis of small intestinal juice and characterisation of radioactive material in the urine indicate that the urine contains radioactive thiamine which was unchanged prior to absorption. (3) In control subjects, the major period of thiamine absorption occurred within the first 2 hours and practically all of the oral dose absorbed was excreted during the first 211. hours. (4) Eight patients with untreated primary malabsorptive disease (idiopathic steatorrhoea) showed a mean urinary excretion of radioactive thiamine significantly less than in the control group. The rate of excretion was markedly reduced but the period of maximal excretion occurred at approximately the same time as in control subjects. Thirteen patients with treated primary malabsorptive disease showed no significant difference from the control group. (5) Ten patients who had undergone gastric surgery and two with resection of the terminal ileum excreted amounts which did not differ from the control group. Normal results were also found in four patients with pernicious anaemia.