TY - JOUR
T1 - Apolipoprotein C-II and C-III levels in hyperlipoproteinemia
AU - Schonfeld, Gustav
AU - George, P. K.
AU - Miller, Joyce
AU - Reilly, Pat
AU - Witztum, Joseph
N1 - Funding Information:
From the Lipid Research Center, Washington University School of Medicine, St. Louis, MO. Receivedfor publication September 12, 1978. Supported by Lipid Research Center NIH Contract NOl-HV-2-2916-L and PHS Grant HL 15308. Address reprint requests to Dr. Gustav Schonfeld. Lipid Research Center, Washington University School of Medicine, Box 8046. 4566 Scott Avenue, St. Louis, MO. 63110. o I979 by Grune & Stratton, Inc. 0026-0495/79/2810-0004%02.00/0
PY - 1979/10
Y1 - 1979/10
N2 - Apoprotein C-II (ApoC-II) functions as a modulator of the hydrolysis of lipoprotein triglycerides by increasing the activity of lipoprotein lipase. Apoprotein C-III (ApoC-III) appears to have an inhibitory effect on ApoC-II-stimulated hydrolysis. Because of the physiologic importance of these apoproteins, we have developed double antibody radioimmunoassays that are capable of measuring the levels of ApoC-II and ApoC-III in human whole plasma and in isolated lipoproteins. ApoC-II and ApoC-III were isolated from very low density lipoproteins by column chromatography. Fractions that were homogeneous on polyacrylamide disc gel electrophoresis and isoelectric focusing and that had the appropriate amino acid compositions were used as antigens, assay standards, and labels. The assays contained 125I-ApoC-II or 125I-ApoC-III (Na125I + lactoperoxidase), rabbit antihuman ApoC-II (or ApoC-III), samples of plasma, lipoproteins, or apoprotein standards, goat antirabbit IgG, and 0.05 M barbital pH 8.6, 0.01% Triton X-100. The assays had the specificities, accuracies, precisions, and immunologic indentities between standards and samples required of all such assays. All of the ApoC-II in plasma in isolated lipoproteins was detected by the ApoC-II assay. ApoC-III1 and ApoC-III2 were equally reactive, and all of the ApoC-III0, ApoC-III1, and ApoC-III2 in plasma and in lipoproteins was detected by the ApoC-III assay. ApoC-II and ApoC-III levels were measured in 171 fasting plasmas taken from normal subjects and patients with type II-V hyperlipidemia. "Normal" values for white subjects were approximately 4 and 16 mg/dl for ApoC-II and ApoC-III, respectively. Levels were several fold elevated in the hyperlipidemias. In normal subjects ∼40% of ApoC-II and ApoC-III were found in the d < 1.006 fraction, ∼15% in d = 1.006-1.063, ∼45% in the d = 1.063-1.21. These distributions were altered in hyperlipidemia. However, in all cases the d>1.21 fraction contained < 5% of either ApoC-II or ApoC-III.
AB - Apoprotein C-II (ApoC-II) functions as a modulator of the hydrolysis of lipoprotein triglycerides by increasing the activity of lipoprotein lipase. Apoprotein C-III (ApoC-III) appears to have an inhibitory effect on ApoC-II-stimulated hydrolysis. Because of the physiologic importance of these apoproteins, we have developed double antibody radioimmunoassays that are capable of measuring the levels of ApoC-II and ApoC-III in human whole plasma and in isolated lipoproteins. ApoC-II and ApoC-III were isolated from very low density lipoproteins by column chromatography. Fractions that were homogeneous on polyacrylamide disc gel electrophoresis and isoelectric focusing and that had the appropriate amino acid compositions were used as antigens, assay standards, and labels. The assays contained 125I-ApoC-II or 125I-ApoC-III (Na125I + lactoperoxidase), rabbit antihuman ApoC-II (or ApoC-III), samples of plasma, lipoproteins, or apoprotein standards, goat antirabbit IgG, and 0.05 M barbital pH 8.6, 0.01% Triton X-100. The assays had the specificities, accuracies, precisions, and immunologic indentities between standards and samples required of all such assays. All of the ApoC-II in plasma in isolated lipoproteins was detected by the ApoC-II assay. ApoC-III1 and ApoC-III2 were equally reactive, and all of the ApoC-III0, ApoC-III1, and ApoC-III2 in plasma and in lipoproteins was detected by the ApoC-III assay. ApoC-II and ApoC-III levels were measured in 171 fasting plasmas taken from normal subjects and patients with type II-V hyperlipidemia. "Normal" values for white subjects were approximately 4 and 16 mg/dl for ApoC-II and ApoC-III, respectively. Levels were several fold elevated in the hyperlipidemias. In normal subjects ∼40% of ApoC-II and ApoC-III were found in the d < 1.006 fraction, ∼15% in d = 1.006-1.063, ∼45% in the d = 1.063-1.21. These distributions were altered in hyperlipidemia. However, in all cases the d>1.21 fraction contained < 5% of either ApoC-II or ApoC-III.
UR - http://www.scopus.com/inward/record.url?scp=0018567934&partnerID=8YFLogxK
U2 - 10.1016/0026-0495(79)90004-0
DO - 10.1016/0026-0495(79)90004-0
M3 - Article
C2 - 226830
AN - SCOPUS:0018567934
SN - 0026-0495
VL - 28
SP - 1001
EP - 1010
JO - Metabolism
JF - Metabolism
IS - 10
ER -