Apolipoprotein A-I metabolism in cynomolgus monkey. Identification and characterization of beta-migrating pools.
Fresh plasma from control (C) and hypercholesterolemic (HC) cynomolgus monkeys was analyzed by agarose electrophoresis-immunoblotting with antibody to cynomolgus monkey apolipoprotein (apo) A-I. Two bands were evident on the autoradiogram: an alpha-migrating band (high density lipoprotein) and a beta-migrating band that comigrated exactly with cynomolgus monkey low density lipoprotein (LDL). The presence of beta-migrating apo A-I in the plasma of these monkeys was confirmed by Geon-Pevikon preparative electrophoresis, crossed immunoelectrophoresis, and isotope dilution studies in which radiolabeled apo A-I was found to equilibrate also with alpha- and beta-migrating pools of apo A-I in the plasma. Subfractionation of C and HC plasma by agarose column chromatography (Bio-Gel A-0.5M and A-15M) followed by agarose electrophoresis-immunoblotting indicated that the beta-migrating apo A-I in C was relatively homogeneous and eluted with proteins of Mr approximately 50 kD [apo A-I(50 kD)], whereas two beta-migrating fractions were identified in HC, one that eluted with the 50-kD proteins, and the other that eluted in the LDL Mr range [apo A-I(LDL)]. The apo A-I(LDL) was precipitated by antibody to cynomolgus monkey apo B. The apo A-I(50 kD) accounted for 5 +/- 1% (mean +/- SD) of the plasma apo A-I in C plasma, and 15 +/- 7% in HC plasma. No apo A-I(LDL) was detected in C plasma, but that fraction accounted for 9 +/- 7% of the apo A-I in HC plasma. These data establish the presence of multiple pools of apo A-I in the cynomolgus monkey, which must be taken into consideration in any comprehensive model of apo A-I metabolism in this species.
Melchior
G W
GW
Upjohn Company, Metabolic Diseases Research, Kalamazoo, Michigan 49001.
Castle
C K
CK
D000818:Animals; D016632:Apolipoprotein A-I; D001054:Apolipoproteins A / Q000097:blood* / Q000302:isolation & purification; D002847:Chromatography, Agarose; D004587:Electrophoresis, Agar Gel; D005260:Female; D006937:Hypercholesterolemia / Q000097:blood*; D015151:Immunoblotting; D007123:Immunoelectrophoresis, Two-Dimensional; D007457:Iodine Radioisotopes; D008075:Lipoproteins, HDL / Q000097:blood* / Q000302:isolation & purification; D008077:Lipoproteins, LDL / Q000097:blood* / Q000302:isolation & purification; D008252:Macaca fascicularis; D008297:Male; D008970:Molecular Weight; D011233:Precipitin Tests
D016632:Apolipoprotein A-I; D001054:Apolipoproteins A; D007457:Iodine Radioisotopes; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL