The rates of plasma clearance of human native low density lipoproteins (LDL) and acetylated human low density lipoproteins (acetyl-LDL) were compared between copper-deficient (CuD) and copper-adequate (CuA) rats. Purified human LDL (d 1.02-1.063) were labeled with 125I and injected to fasted recipient rats intravenously. At different time intervals plasma clearance of 125I radioactivity was measured. The percent of clearance was calculated based on the total plasma volume, as determined by a radioisotopic dilution method. Native human 125I-LDL were cleared at a faster rate in CuD, compared with CuA rats. The half-times (t 1 2) of 125I-LDL clearance are 4.90 ± 0.20 and 5.80 ± 0.30 hours in CuD and CuA rats, respectively. The plasma trichloroacetic acid-soluble 125I-radioactivity was significantly and steadily increased in CuD rats at each interval, reflecting the faster clearance and degradation of LDL in those rats. The plasma removal of 125I-acetyl-LDL was faster compared with that of 125I-LDL. The half-times (t 1 2) of acetyl-LDL in CuD and CuA rats are 5.20 ± 0.06 and 5.16 ± 0.08 minutes, respectively, with no significant difference between the groups. The data indicates that the uptake of LDL via the "scavenger" receptor remains unaffected in copper-deficient rats. The faster removal of the unmodified (native) LDL in CuD group suggests that the apoB,E receptor is up-regulated in copper-deficient rats and that the hypercholesterolemia observed in copper deficiency is not associated with the defective uptake of LDL by the apoB,E-receptor dependent mechanism.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etsu-works-14821 |
| Date | 01 January 1992 |
| Creators | Koo, Sung I., Lee, Christine C., Stone, William L., Scott, Robert L. |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | ETSU Faculty Works |
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