ISSN:
1432-0878
Keywords:
Endocardium
;
Endothelium
;
Collagen
;
Catabolism
;
Endocytosis
;
Reticuloendothelial system
;
Cod Gadus morhua, (Teleostei)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract The cells responsible for the clearance of collagen were studied in cod. Cod collagen labelled with the lysosomal trap-label 125I-tyramine cellobiose was cleared from the circulation with a t1/2 of 15 min. 1 h After injection 75%, 17% and 8% of the label were recovered in the heart, liver and blood, respectively. 24 h After administration of collagen labelled conventionally with 125I to allow escape of labelled degradation product from the site of uptake, 80% of the label had left the heart, signifying degradation. When collagen was tagged with 125I-tyramine cellobiose, heart-associated radioactivity did not decrease after 24 h, indicating intralysosomal degradation. Fluorescence microscopy revealed that i.v. injected fluorescently-labelled collagen accumulated in discrete vesicles of cells lining the endocardial blood space of both atrium and ventricle. Conventional and immuno-electron microscopy showed that these cells contained numerous coated pits and vesicles reflecting active endocytosis, and that ligand lined the limiting membrane of early endosomes. Intravenously injected 2 μm latex accumulated mainly in kidney. We conclude that the population of non-macrophagic endocardial cells are important for the turnover of collagen in cod. These cells therefore resemble sinusoidal endothelial cells of salmon kidney and mammalian liver.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00304509
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