Diurnal variations in cobalamin binding plasma proteins.
The diurnal variations in cobalamin-binding plasma proteins were studied in 10 healthy volunteers. The unsaturated cobalamin-binding capacities of transcobalamins (TC-II and R-binders), P-cobalamin and P-protein were measured every third hour during 24h. Only small variations within an interval of +/- 20% were found. Highly significant decrements during the night were a uniform finding. After correction for variations of total plasma protein, the changes became less prominent, but still significant for P-cobalamin and P-R-binders. Hence the mean values of P-R-binders and P-cobalamin were 113 and 533 pmol/1 at 9:00 h, and decreased 12 and 8%, respectively, at 3:00 h. When using cobalamin binding plasma proteins in the monitoring of various malignant, haematological and autoimmune disorders, the specimens should, therefore, be collected at defined hours and in a uniform posture.
D000328:Adult; D001798:Blood Proteins / Q000378:metabolism*; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D011187:Posture; D012709:Serum Albumin / Q000378:metabolism; D014155:Transcobalamins / Q000378:metabolism*
D001798:Blood Proteins; D012709:Serum Albumin; D014155:Transcobalamins