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Aspects of Folate Metabolism in Renal Failure
Author(s) -
Retief F. P.,
Heyns A. du P.,
Oosthuizen Mariëtha,
Reenen O. R.
Publication year - 1977
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1111/j.1365-2141.1977.tb00664.x
Subject(s) - urine , chemistry , metabolism , ingestion , medicine , endocrinology , excretion , chromatography , biochemistry
Plasma and urine folate fractions were evaluated after ingestion of radio‐active N5‐methyl‐tetrahydrofolic acid by a normal control (subject 1), a patient on maintenance haemodialysis for chronic glomerulonephritis (subject 2), and an anephric patient on haemodialysis (subject 3). In subjects 1 and 2 maximal plasma radiofolate peaks appeared within 1 h of isotope ingestion. In subject 3 the radio‐folate peak was delayed for 6 h although the total biofolate fraction reached a maximum at 0.5 h (comparable with findings in subject 2). Sephadex DEAE A50 chromatography showed the radiofolate fraction in subject 1 to be compatible with N5‐methyl‐tetrahydrofolic acid (peak 1). In subject 2 additional radiofolate peaks 2 and 3 were found. The nature of peak 2 is unknown but peak 3 may represent 10‐formyl‐tetrahydrofolate. Peak 1 was minimally present in subject 3. This limited study suggests a defect of methyl‐tetrahydrofolate metabolism in the anephric state unassociated with defective renal excretion per se . In normal urine, peak 2 predominated while urine of subject 2 had a predominant peak 3 and lesser peaks 1 and 2. Compared with the control, uraemic subjects 2 and 3 showed greatly decreased dialysis‐resistant (bound) plasma radiofolate fractions; all urinary radiofolates were fully dialysable. The unexplained radiofolate ‘binder’detected with haemoglobin‐coated charcoal adsorption in urine (subject 2) and occasionally in plasma, probably represents an artefact. Plasma from 27 uraemic subjects showed no abnormal in vitro radiofolate binding capacity.