Human apolipoprotein A-I and A-II metabolism
The kinetics of the major apolipoproteins (apo) of plasma high density lipoproteins (HDL), apoA-I and apoA-II, were examined in a total of 44 individual tracer studies in 22 normal male and female subjects. Following the intravenous injection of radioiodinated HDL, the specific radioactivity decay o...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
1982-08-01
|
| Series: | Journal of Lipid Research |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520380871 |
| _version_ | 1819291016739422208 |
|---|---|
| author | E J Schaefer L A Zech L L Jenkins T J Bronzert E A Rubalcaba F T Lindgren R L Aamodt H B Brewer, Jr |
| author_facet | E J Schaefer L A Zech L L Jenkins T J Bronzert E A Rubalcaba F T Lindgren R L Aamodt H B Brewer, Jr |
| author_sort | E J Schaefer |
| collection | DOAJ |
| description | The kinetics of the major apolipoproteins (apo) of plasma high density lipoproteins (HDL), apoA-I and apoA-II, were examined in a total of 44 individual tracer studies in 22 normal male and female subjects. Following the intravenous injection of radioiodinated HDL, the specific radioactivity decay of apoA-I within HDL (residence time, 5.07 +/- 1.53 days), as determined by column chromatography, was significantly (P < 0.01) faster than that of apoA-II (residence time, 5.96 +/- 1.84 days). The specific radioactivity decay of apoA-I within HDL when labeled on HDL or as apoA-I was found to be almost identical. Similar results were obtained for apoA-II. Analysis of simultaneous paired radiolabeled apoA-I and apoA-II studies revealed that the mean apoA-I plasma residence time (4.46 +/- 1.04 days) was significantly (P < 0.01) shorter than that for apoA-II (4.97 +/- 1.06 days). Females had significantly (P < 0.01) higher apoA-I plasma concentrations (124 +/- 24 mg/dl) and apoA-I synthesis rates (13.58 +/- 2.23 mg/kg. day) than did males (108 +/- 16 mg/dl, and 11.12 +/- 1.92 mg/kg. day, respectively). Plasma apoA-I levels were correlated with plasma apoA-I residence times, but not synthesis rates; and apoA-II concentrations were correlated only with apoA-II whole body residence times. ApoA-I and apoA-II plasma residence times were inversely correlated with plasma triglyceride levels. These data are consistent with the following concepts: 1) labeling of apoA-I and apoA-II as apolipoproteins or on HDL does not affect their specific radioactivity decay within HDL; 2) the mean residence time of apoA-I both in plasma and in HDL is significantly shorter than that of apoA-II; 3) the increased apoA-I levels seen in female subjects are due to increased apoA-I synthesis; and 4) the plasma apoA-I residence time, which is inversely correlated with plasma triglyceride levels, is an important determinant of apoA-I concentration in both males and females.-Schaefer, E. J., L. A. Zech, L. L. Jenkins, T. J. Bronzert, E. A. Rubalcaba, F. T. Lindgren, R. L. Aamodt, and H. B. Brewer, Jr. Human apolipoprotein A-I and A-II metabolism. |
| first_indexed | 2024-12-24T03:31:56Z |
| format | Article |
| id | doaj.art-fbb8cc26ed854cfea5f8c8a25ab48cf2 |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-24T03:31:56Z |
| publishDate | 1982-08-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-fbb8cc26ed854cfea5f8c8a25ab48cf22022-12-21T17:17:11ZengElsevierJournal of Lipid Research0022-22751982-08-01236850862Human apolipoprotein A-I and A-II metabolismE J SchaeferL A ZechL L JenkinsT J BronzertE A RubalcabaF T LindgrenR L AamodtH B Brewer, JrThe kinetics of the major apolipoproteins (apo) of plasma high density lipoproteins (HDL), apoA-I and apoA-II, were examined in a total of 44 individual tracer studies in 22 normal male and female subjects. Following the intravenous injection of radioiodinated HDL, the specific radioactivity decay of apoA-I within HDL (residence time, 5.07 +/- 1.53 days), as determined by column chromatography, was significantly (P < 0.01) faster than that of apoA-II (residence time, 5.96 +/- 1.84 days). The specific radioactivity decay of apoA-I within HDL when labeled on HDL or as apoA-I was found to be almost identical. Similar results were obtained for apoA-II. Analysis of simultaneous paired radiolabeled apoA-I and apoA-II studies revealed that the mean apoA-I plasma residence time (4.46 +/- 1.04 days) was significantly (P < 0.01) shorter than that for apoA-II (4.97 +/- 1.06 days). Females had significantly (P < 0.01) higher apoA-I plasma concentrations (124 +/- 24 mg/dl) and apoA-I synthesis rates (13.58 +/- 2.23 mg/kg. day) than did males (108 +/- 16 mg/dl, and 11.12 +/- 1.92 mg/kg. day, respectively). Plasma apoA-I levels were correlated with plasma apoA-I residence times, but not synthesis rates; and apoA-II concentrations were correlated only with apoA-II whole body residence times. ApoA-I and apoA-II plasma residence times were inversely correlated with plasma triglyceride levels. These data are consistent with the following concepts: 1) labeling of apoA-I and apoA-II as apolipoproteins or on HDL does not affect their specific radioactivity decay within HDL; 2) the mean residence time of apoA-I both in plasma and in HDL is significantly shorter than that of apoA-II; 3) the increased apoA-I levels seen in female subjects are due to increased apoA-I synthesis; and 4) the plasma apoA-I residence time, which is inversely correlated with plasma triglyceride levels, is an important determinant of apoA-I concentration in both males and females.-Schaefer, E. J., L. A. Zech, L. L. Jenkins, T. J. Bronzert, E. A. Rubalcaba, F. T. Lindgren, R. L. Aamodt, and H. B. Brewer, Jr. Human apolipoprotein A-I and A-II metabolism.http://www.sciencedirect.com/science/article/pii/S0022227520380871 |
| spellingShingle | E J Schaefer L A Zech L L Jenkins T J Bronzert E A Rubalcaba F T Lindgren R L Aamodt H B Brewer, Jr Human apolipoprotein A-I and A-II metabolism Journal of Lipid Research |
| title | Human apolipoprotein A-I and A-II metabolism |
| title_full | Human apolipoprotein A-I and A-II metabolism |
| title_fullStr | Human apolipoprotein A-I and A-II metabolism |
| title_full_unstemmed | Human apolipoprotein A-I and A-II metabolism |
| title_short | Human apolipoprotein A-I and A-II metabolism |
| title_sort | human apolipoprotein a i and a ii metabolism |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520380871 |
| work_keys_str_mv | AT ejschaefer humanapolipoproteinaiandaiimetabolism AT lazech humanapolipoproteinaiandaiimetabolism AT lljenkins humanapolipoproteinaiandaiimetabolism AT tjbronzert humanapolipoproteinaiandaiimetabolism AT earubalcaba humanapolipoproteinaiandaiimetabolism AT ftlindgren humanapolipoproteinaiandaiimetabolism AT rlaamodt humanapolipoproteinaiandaiimetabolism AT hbbrewerjr humanapolipoproteinaiandaiimetabolism |