RENAL ELIMINATION OF ISLET AMYLOID POLYPEPTIDE

Six healthy volunteers showed significantly higher plasma islet amyloi d polypeptide levels following an oral glucose tolerance test compared to fasting levels. The urine IAPP concentration before and after the OGTT was comparable to that in plasma. Reverse phase HPLC and radioimm unoassay analysis of urine samples revealed a single IAPP-immunoreacti ve peak. Before hemodialysis, the plasma levels of IAPP and C-peptide, but not of insulin, were significantly elevated in eight fasting pati ents with chronic renal failure, compared to eight healthy matched con trol subjects. After hemodialysis, there was a tendency for decreased IAPP levels compared to before dialysis. In summary, elevated levels o f plasma IAPP were found in patients with chronic renal failure and th e peptide is eliminated by hemodialysis. Furthermore, immunoreactive I APP is normally present in the urine, These results suggest that IAPP is, at least in part, renally eliminated from the plasma by excretion (glomerular filtration and/or tubular secretion). (C) 1997 Academic Pr ess.