Albumin metabolism and gastrointestinal loss of protein in chronic renal failure

The catabolism of albumin labelled with 125I has been studied in 10 patients with advanced renal failure and in 5 with nephrotic syndrome. In 10 patients the gastrointestinal protein loss was studied simultaneously by determing the faecal excretion during 7 days of 51Cr after i.v. administration of 51Cr-labelled chromic chloride. The results were related to a control group in which 12 subjects were studied with respect to albumin catabolism and 17 with respect to the gastrointestinal protein losses. The results showed that: 1) In the two patient groups the means for serum albumin concnetration and the intravascular albumin pool, expressed as g or g/kg b.wt., were significantly decreased compared with those of the control group. 2) The two patient groups had an increased extravascular albumin pool as well as an elevated ration between extra- and intravascular pools. 3) The mean albumin catabolic rate was not increased in the renal insufficiency group, expressed as a percentage of the intravascular pool/24 h or as g/24 h. In the patients with nephrotic syndrome, however, it was significantly increased. 4) The renal insufficiency group had a mean cumulative 51Cr excretion during 7 days of 1.6+/- 0.80% of the given dose, the control group 0.63+/- 0.30%. This difference is highly significant. The patients with nephrotic syndrome did not differ from the control group.