The role of the kidney in the elimination of pancreatic lipase and amylase from blood.

Two clinical observations indicate that the kidney plays the main role in the elimination of lipase and amylase from the circulation: 1. in patients with uncomplicated acute pancreatitis the decrease of the activity of both enzymes in the serum ran almost in parallel. The half life for lipase was found to be 6.9-13.7 h, and somewhat higher figures (9.3-17.7 h) were calculated for amylase; 2. in patients with reduced glomerular filtration rate the serum activity of either or of both enzymes was distinctly elevated. The contribution of the kidney to the elimination of lipase and amylase from blood was studied in the rat. After an intravenous bolus injection of homologous lipase and amylase, the serum activity of both enzymes decreased rapidly. The half-life of lipase was 18.1 min, that of amylase 20.5 min. Up to 30% of the injected amylase but only traces of lipase activity were recovered in the urine. In animals with ligated kidneys the serum half-life of both enzymes was 3 times longer. Our results indicate that lipase as well as amylase are removed from the serum mainly by glomerular filtration at nearly the same rate. Reabsorption of lipase is almost complete, in contrast to that of amylase. It is suggested that the differences in the renal handling of both enzymes are due to their differing affinities for hydrophilic and hydrophobic surfaces.