Abstract
WE have recently shown1 that patients with folic acid and/or vitamin B12 (FA–B12) deficiency have an increased excretion of 4-aminoimidazole-5-carboxamide (AIC) compared with anaemic patients who are not so deficient, or with non-anaemic hospital patients. A FIGLU test, using an oral load of 15 g L-histidine hydrochloride, was performed on many of these patients as a diagnostic procedure; since a haematological response has been observed in such patients following histidine dosage2,3, which would imply a partial correction at least of the disordered nucleoprotein metabolism present in these deficiencies, we have taken the opportunity to investigate its effect on the urinary excretion of AIC, itself an intermediary in purine synthesis. For this purpose urine passed between 4 and 8 h after histidine dosage was examined (Period 3); urines collected during one hour in the morning immediately before the test (Period 2) and in some cases for a similar 5-h period the previous afternoon (Period 1) served as controls. For comparison, similar collections were made from 8 normal adult volunteers and 3 patients who had anaemia not associated with FA–B12 deficiency. No dietary restrictions were imposed during the test. Urines were preserved with 1 ml. 6 N HCl per h of the save and stored at 4° C. AIC was determined by an ion-exchange chromatographic technique4. In order to minimize any errors in the timing of the urine collections all results were expressed as AIC µg/mg creatinine.
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MIDDLETON, J., COWARD, R. & SMITH, P. Effect of Histidine on the Urinary Excretion of 4-Aminoimidazole-5-carboxamide. Nature 207, 310 (1965). https://doi.org/10.1038/207310a0
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DOI: https://doi.org/10.1038/207310a0
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