Measurement of apolipoprotein A-I in rat high density lipoprotein and in rat plasma by radioimmunoassay
A double antibody radioimmunoassay (RIA) for rat apolipoprotein A-I is reported. The ApoA-I isolated from delipidated HDL by gel filtration yielded a single band on polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS), and its amino acid composition resembled that reported by others. A...
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doaj-aab9e6d6e7d94f51abd52164bba9e94d2021-04-24T05:49:53ZengElsevierJournal of Lipid Research0022-22751976-01-011712529Measurement of apolipoprotein A-I in rat high density lipoprotein and in rat plasma by radioimmunoassayG Schonfeld0M S Frick1A P Bailey2Lipid Research Center, Departments of Preventive Medicine and Medicine, Washington University School of Medicine, St. Louis, Miwuri 63110Lipid Research Center, Departments of Preventive Medicine and Medicine, Washington University School of Medicine, St. Louis, Miwuri 63110Lipid Research Center, Departments of Preventive Medicine and Medicine, Washington University School of Medicine, St. Louis, Miwuri 63110A double antibody radioimmunoassay (RIA) for rat apolipoprotein A-I is reported. The ApoA-I isolated from delipidated HDL by gel filtration yielded a single band on polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS), and its amino acid composition resembled that reported by others. ApoA-I was iodinated by lactoperoxidase and the resulting 125I-apoA-I was purified by gel filtration. Up to 93% of 125I-apoA-I was precipitable by antibody and > 99% of bound 125I-apoA-I was displaced by “cold” apoA-I. Other rat lopoproteins and apolipoproteins did not react in this system. Human plasma were also not reactive, nor were dog, goat, and sheep plasmas.Rat intact HDL displaced 125I-apoA-I in parallel with “cold” apoA-I; however, only about 10% of the apoA-I in intact HDL reacted in the assay. Removal of the lipid from HDL by extraction with ether-ethanol solutions increased the reactivity of apoA-I to levels expected from studies of the apeA-I content of HDL by column chromatography and SDS disc gel electrophoresis. Plasmas from Sprague-Dawley male and female rats also displaced counts in parallel with apoA-I. Apparent plasma levels of apoA-I ranged from 2 to 7 mg/dl in unextracted plasma. When assay incubations were carried out for two hours a t 37°C at theb eginning of the assay and again right after the addition of the second antibody, similar low results were obtained. Lipid extraction increased apparent levels about 9-fold to 39 ± 8 mg/dl for Sprague-Dawley males (n = 14) and 47 ± 6 mg/dl for females (n = 5). ApoA-I was not lost during extraction. Heating of plasmas to 52°C before assay yielded levels of 26 ± 4 mg/dl. Thus, extraction of plasmas appears to be necessary to obtain accuralteev els of apoA-I in this assay system.http://www.sciencedirect.com/science/article/pii/S0022227520370127rat high density lipoproteinapolipoprotein A-Iradioimmunoassay |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
G Schonfeld M S Frick A P Bailey |
spellingShingle |
G Schonfeld M S Frick A P Bailey Measurement of apolipoprotein A-I in rat high density lipoprotein and in rat plasma by radioimmunoassay Journal of Lipid Research rat high density lipoprotein apolipoprotein A-I radioimmunoassay |
author_facet |
G Schonfeld M S Frick A P Bailey |
author_sort |
G Schonfeld |
title |
Measurement of apolipoprotein A-I in rat high density lipoprotein and in rat plasma by radioimmunoassay |
title_short |
Measurement of apolipoprotein A-I in rat high density lipoprotein and in rat plasma by radioimmunoassay |
title_full |
Measurement of apolipoprotein A-I in rat high density lipoprotein and in rat plasma by radioimmunoassay |
title_fullStr |
Measurement of apolipoprotein A-I in rat high density lipoprotein and in rat plasma by radioimmunoassay |
title_full_unstemmed |
Measurement of apolipoprotein A-I in rat high density lipoprotein and in rat plasma by radioimmunoassay |
title_sort |
measurement of apolipoprotein a-i in rat high density lipoprotein and in rat plasma by radioimmunoassay |
publisher |
Elsevier |
series |
Journal of Lipid Research |
issn |
0022-2275 |
publishDate |
1976-01-01 |
description |
A double antibody radioimmunoassay (RIA) for rat apolipoprotein A-I is reported. The ApoA-I isolated from delipidated HDL by gel filtration yielded a single band on polyacrylamide gel electrophoresis in sodium dodecyl sulfate (SDS), and its amino acid composition resembled that reported by others. ApoA-I was iodinated by lactoperoxidase and the resulting 125I-apoA-I was purified by gel filtration. Up to 93% of 125I-apoA-I was precipitable by antibody and > 99% of bound 125I-apoA-I was displaced by “cold” apoA-I. Other rat lopoproteins and apolipoproteins did not react in this system. Human plasma were also not reactive, nor were dog, goat, and sheep plasmas.Rat intact HDL displaced 125I-apoA-I in parallel with “cold” apoA-I; however, only about 10% of the apoA-I in intact HDL reacted in the assay. Removal of the lipid from HDL by extraction with ether-ethanol solutions increased the reactivity of apoA-I to levels expected from studies of the apeA-I content of HDL by column chromatography and SDS disc gel electrophoresis. Plasmas from Sprague-Dawley male and female rats also displaced counts in parallel with apoA-I. Apparent plasma levels of apoA-I ranged from 2 to 7 mg/dl in unextracted plasma. When assay incubations were carried out for two hours a t 37°C at theb eginning of the assay and again right after the addition of the second antibody, similar low results were obtained. Lipid extraction increased apparent levels about 9-fold to 39 ± 8 mg/dl for Sprague-Dawley males (n = 14) and 47 ± 6 mg/dl for females (n = 5). ApoA-I was not lost during extraction. Heating of plasmas to 52°C before assay yielded levels of 26 ± 4 mg/dl. Thus, extraction of plasmas appears to be necessary to obtain accuralteev els of apoA-I in this assay system. |
topic |
rat high density lipoprotein apolipoprotein A-I radioimmunoassay |
url |
http://www.sciencedirect.com/science/article/pii/S0022227520370127 |
work_keys_str_mv |
AT gschonfeld measurementofapolipoproteinaiinrathighdensitylipoproteinandinratplasmabyradioimmunoassay AT msfrick measurementofapolipoproteinaiinrathighdensitylipoproteinandinratplasmabyradioimmunoassay AT apbailey measurementofapolipoproteinaiinrathighdensitylipoproteinandinratplasmabyradioimmunoassay |
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