The renal handling of biologically active peptides.
With the use of the protease inhibitor from bovine organs--Trasylol-- as a model, we studied the pinocytic transport of peptides in the kidney. Rats were injected with the 125I-labeled peptide and killed at different times thereafter. Kidney homogenates were subfractionated by differential and sucrose gradient centrifugation. Radioactivity was measured in the fractions in order to study the time-dependent fixation of the peptide to different cell organelles. With short survival periods, the protease inhibitor is recovered in the brush-border fraction, with longer periods, a shift towards the lysosome fraction takes place. Thus, the renal transport of the protease inhibitor consists of three steps: binding to the brush border, incorporation in micropinocytic vesicles and transport in phagolysosomes.
D000818:Animals; D007611:Aprotinin / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D066298:In Vitro Techniques; D007668:Kidney / Q000378:metabolism* / Q000648:ultrastructure; D008247:Lysosomes / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors
D010455:Peptides; D007611:Aprotinin