The Measurement of Apolipoprotein A-I and A-II Levels in Men and Women by Immunoassay

Abstract

A B S T R A C T To study apolipoprotein A-II, a simple, precise, and accurate immunodiffusion assay was developed and applied in a population sample of industrial employees. Apolipoprotein A-II (A-II) did not increase with age in men (r = -0.20, n = 172), but showed a slight increase with age in women (0.1 mg/dl per yr, r = 0.20, n = 188). A-II correlated significantly with apolipoprotein A-I (A-I) (r = 0.71) and high density lipoprotein (HDL) cholesterol (men, r = 0.64; women, r = 0.49). The A-I/A-II ratio was significantly related to HDL cholesterol (men, r = 0.29; women, r = 0.44). Women on no medication (n = 92) had A-II levels similar to men (34+5 and 33+5 mg/dl, mean±+SD, respectively), whereas women on oral contraceptives or estrogens had significantly higher levels (39±6 mg/dl, n = 75, P < 0.01). The plasma A-I/A-Il weight ratio was 3.6±0.4 for men and 3.8±0.5 for women. In the d = 1.10-1.21 subfraction, both males and females had similar A-I, A-II, and HDL cholesterol levels (men: mean, 97, 27, and 32 mg/dl, respectively; women: mean, 104, 28, and 36 mg/dl, respectively). Women had approximately twice the amount of A-I, A-II, and HDL cholesterol than men in the d = 1.063-1.10 fraction (men: mean, 10, 2, aind 10 mg/dl, respectively; women: mean, 24, 4, and 19 mg/dl, respectively). The A-I/A-II weight ratio in the d = 1.063-1.10 fraction (men, 5.1±0.7; women, 6.1±1.3) was significantly greater (P < 0.01) than that in the d = 1.10-1.21 fraction (men, 3.7 ±0.2; women, 3.8±0.2). Furthermore, the weight ratio of cholesterol to total apoprotein A in the d = 1.063-1.10 fraction (men, 0.75±0.09; women, 0.67±0.05) was significantly higher (P < 0.01) than that found in the d = 1.10-1.21 fraction (men, 0.26±0.04, women, 0.28 A preliminary report of part of this work was presented at the 49th Annual Scientific Meeting of the American Heart Association in Miami, Fla. and was published in abstract form in 1976. Circulation. 54 (Suppl 2): 367.Received for publication 21 ±0.05). Thus, the compositions of HDL hydrated density subclasses are significantly different from each other. These results suggest that the differences in HDL between men and women are due primarily to differences in the relative proportions of HDL subclasses rather than to the intrinsic differences in HDL structure.

Effect of Atorvastatin on High-Density Lipoprotein Apolipoprotein A-I Production and Clearance in the New Zealand White Rabbit

“…14 ApoA-I concentrations were determined via electroimmunoassay using a goat antirabbit apoA-I antibody raised in our laboratory by a modification of methods previously described. 17 …”

Associations of lecithin: cholesterol acyltransferase (LCAT) mass concentrations with exercise, weight loss, and plasma lipoprotein subfraction concentrations in men

“…Results are also described for the peak flotation rate (S f ) of the LDL-mass distribution [12,13]. Plasma lipoprotein cholesterol concentrations were measured directly by the methods of the Lipid Research Clinics [14], plasma apolipoprotein B concentrations were assessed by radioimmunoassay [15], apolipoprotein A-I and A-II concentrations were measured by radialimmunodiffusion [16], and LCAT mass was measured by double antibody radioimmunoassay [17]. Assays of apolipoproteins and LCAT were made on all samples at the end of the study using plasmas that had been stored at −80°C.…”

HDL Apolipoprotein A-I and HDL Apolipoprotein A-II Concentrations in Male Company Employees in Westphalia Aged 40 Years and Older

“…Furthermore, it has been reported that alcohol consumption, which is known to be associated with high HDL cholesterol (25 -27) and frequently with hypertriacylglycerolaemia (28, 29), mainly resulted in an enhanced level of HDL 3 mass without affecting HDL 2 mass (30). It has been shown that the apolipoprotein A-I/apolipoprotein A-II ratio in HDL/2 is higher than that in HDL 3 (31,32). Therefore, in individuals with heigh HDL cholesterol levels (which are associated with lower triacylglycerol) and a similarly high apolipoprotein A-I/apolipoprotein A-II ratio, a higher HDL2/HDL 3 ratio may exist in comparison to individuals with lower HDL cholesterol levels (which are associated with higher triacylglycerol) and a similarly low apolipoprotein A-I/apolipoprotein A-II ratio.…”