Total Nondialyzable Solids (Tnds) in Human Urine V. Subfractionation of the Ultrafiltrate (Uf-O) Fraction *

Abstract

A procedure has been reported (1) for the re--producible separation of the total nondialyzable solids (TNDS) of normal human urine into three primary fractions. The most abundant of the -three fractions, designated UF-O, was separated from the other two by virtue of its passage through a collodion ultrafilter membrane. The overall chemical composition of fraction UF-O was described, but no further information was then available. Accordinigly, we have devised a procedure for the separation of this material into subfractions. While these subfractions appear to be cleanly separated, they are all probably mixtures of various chemical compounds. The method yields consistent results and therefore seems to be a useful tool for the study of possible changes in physiological and pathological conditions, and as an intermediate step in the ultimate separation of the components of UF-O.This report describes the procedure for the subfractionation of the UF-O and the results obtained with it, including the range of normal daily variation in the excretion of the subfractions and their overall chemical composition. Some pertinent ancillary information about the TNDS, acquired during these experiments, is also included. MATERIALS AND METHODSSubjects. Three 24 hour urine specimens were collected, with chloroform preservative, by each of 12 normally active, healthy subjects (eight male, four female). With one exception, they were the same sub-