Metabolic fate of rat heart endothelial lipoprotein lipase

Journal Article · Thu Sep 01 04:00:00 EDT 1988 · Am. J. Physiol.; (United States)

OSTI ID:7095356

Chajek-Shaul, T; Bengtsson-Olivecrona, G; Peterson, J; Olivecrona, T

When isolated rat hearts were perfused with medium containing 125I-labeled bovine lipoprotein lipase (LPL), they bound both lipase activity and radioactivity. More than 80% of the bound lipase could be rapidly released by heparin. Low concentrations of bovine LPL displaced 50-60% of the endogeneous, endothelial-bound LPL. Higher concentrations caused additional binding. Both binding and exchange were rapid processes. The hearts continuously released endogenous LPL into the medium. An antiserum that inhibited bovine but not rat LPL was used to differentiate endogeneous and exogeneous LPL activity. When the pool of endothelial LPL was labeled with bovine 125I-labeled LPL and then chased with unlabeled bovine LPL, approximately 50% of the labeled lipase was rapidly displaced. During chase perfusion with medium only, catalytically active bovine LPL appeared in the perfusate. The rate of release was similar to that observed for endogeneous LPL activity and amounted to 10-13% of the heparin-releasable fraction in the first 5 min of perfusion. There was little or no degradation of bovine 125I-labeled LPL to fragments or acid-soluble products. These results indicate that endothelial LPL is accessible for exchange with exogeneous LPL and that detachment rather than degradation may be the pathway for catabolism of endothelial LPL.

• Research Organization: Univ. of Umea (Sweden)
• OSTI ID: 7095356
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 255; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOLOGICAL PATHWAYS
BODY
CARBOXYLESTERASES
CARDIOVASCULAR SYSTEM
CATTLE
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
ELECTRON CAPTURE RADIOISOTOPES
ENDOTHELIUM
ENZYME ACTIVITY
ENZYMES
ESTERASES
ESTERS
FASTING
HEART
HYDROLASES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIPASE
LIPIDS
LIPOPROTEINS
MAMMALS
METABOLISM
MUSCLES
MYOCARDIUM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PERFUSED ORGANS
PROTEINS
RADIOISOTOPES
RATS
RODENTS
RUMINANTS
TISSUES
TRACER TECHNIQUES
TRIGLYCERIDES
VERTEBRATES