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- Title
Renal handling of plasma high density lipoprotein.
- Authors
Peterson, Darryl R.; Hjelle, J. Thomas; Carone, Frank A.; Moore, Paul A.
- Abstract
Renal handling of plasma high density lipoprotein. Renal tubular reabsorption and hydrolysis of plasma high density lipoprotein (HDL3) were studied. Rabbit proximal straight nephron segments were microperfused in vitro with iodinated HDL3. Progressive luminal uptake and cellular accumulation of radiolabeled material were observed during an initial phase, followed by a reduction in sequestration and the appearance of 12I-label in the bathing medium. to detect proteolysis, collected perfusates and bathing media were analyzed for trichloracetic acid soluble radioactivity. 125I-HDL3 in the luminal fluid was intact, but metabolites appeared in the bathing medium. Electron microscopic radioautography, demonstrated endocytic uptake of 125I-HDL3 at the luminal membrane of the proximal tubule and movement of g rains into lysosome-like dense bodies. Incubation and radiolabeled HDL3 in the presence of renal homogenates resulted in proteolytic activity with an acidic pH optimum. Analytical cell fractionation studies indicated that hydrolysis of the protein component is associated with lysosomes derived from proximal kidney tubules. Collectively, the data show that plasma HDL3 can be reabsorbed in the proximal nephron by a mechanism involving endocytosis at the luminal membrane, followed by proteolysis at lysosomes.
- Subjects
HIGH density lipoproteins; BLOOD lipoproteins; LABORATORY rabbits; PROTEOLYSIS; PROTEIN metabolism
- Publication
Kidney International, 1984, Vol 26, Issue 4, p411
- ISSN
0085-2538
- Publication type
Article
- DOI
10.1038/ki.1984.190