PLASMA-IMMUNOREACTIVE LEPTIN CONCENTRATION IN END-STAGE RENAL-DISEASE

1. Leptin is thought to be an inhibitor of appetite. As the kidney hel ps clear several polypeptide hormones, plasma leptin may accumulate in end-stage renal disease. 2. Plasmaimmunoreactive leptin was measured in four groups of subjects: haemodialysis, continuous ambulatory perit oneal dialysis and renal transplant patients and a group of healthy co ntrols, Leptin was also measured before and after a single dialysis se ssion. 3. There was a strong correlation between plasma immunoreactive leptin and body mass index in all groups except female haemodialysis patients, Leptin was higher in females than in males in all groups whe n controlled for body mass index, Mean plasma leptin [mean (SD)] was s ignificantly higher in all renal groups [haemodialysis, 15.1 (3.6) ng/ ml; continuous ambulatory peritoneal dialysis, 25.4 (4.3) ng/ml; trans plants, 11.6 (2.6) ng/ml] compared with controls [5.3 (2.3) ng/ml]. Th ere was a significant difference in the regression equations relating leptin and body mass index (dialysis > transplants > controls), even w hen controlled for gender, Leptin correlated modestly with serum creat inine in non-dialysis subjects. Plasma leptin immunoreactivity was sli ghtly reduced by haemodialysis, but postdialysis leptin was still sign ificantly higher than that found in controls. 4. Chromatographic chara cterization of the high level of leptin immunoreactivity found in haem odialysis subjects showed a single elution peak corresponding to that of the highly purified human leptin standard. 5. In conclusion, leptin is higher than expected for body mass index in end-stage renal diseas e. Hyperleptinaemia could contribute to the anorexia and poor nutritio nal status commonly seen in renal failure.