STUDIES OF THIAMINE METABOLISM IN MAN. II. THIAMINE AND PYRIMIDINE EXCRETION WITH SPECIAL REFERENCE TO THE RELATIONSHIP BETWEEN INJECTED AND EXCRETED THIAMINE IN NORMAL AND ABNORMAL SUBJECTS 1

Abstract

The thiamine balance was studied in 10 subjects (6 normal, 1 hyperthyroid, 2 chronic diabetics, and 1 chronic diabetic with carcinoma of the pancreas), in regard to (1) relation between intake and excretion in normal and abnormal subjects, (2) the fate of intramusc. admin. thiamine, (3) the relation between thiamine intake and "pyrimidine" excretion, and (4) the rate of excretion of excess stores of thiamine. Increasing thiamine intake up to 7-10 mg./day was accompanied by increasing urinary thiamine and pyrimidine; intake above 10 mg./day increased only the thiamine. Urinary thiamine and pyrimidine in normal subjects accounted for practically all of the admin. thiamine, and the ability to convert thiamine to pyrimidine reached a maximum at an intake of 10 mg. Storage of thiamine is limited to 2 or 3 times the amount normally present, and this store disappears logarithmically upon return of thiamine intake to normal levels. Thiamine excretion by abnormal subjects was significantly less than that anticipated from results obtained with normal subjects.