title: Quantitation of apolipoprotein A-I of human plasma high density lipoprotein.
abstract: High density lipoproteins (HDL) may be controlled via their major apolipoprotein, A-I. To study this apolipoprotein, a simple, precise, and accurate immunodiffusion assay for A-I was developed and applied in a sample of Bell Telephone Company employees. A-I showed a slight increase with age in men (r=0.11, n=263) and women (r=0.15, n=257). A-I correlated closely with HDL cholesterol (r=0.72). It was weakly related to total triglyceride in women (r=0.24) but was inversely related in men (r=-0.17). Women on estrogen had the highest A-I levels (149 mg/dl +/- 26, x +/- S.D., n=29, p is less than 0.05), followed by women on combination oral contraceptives (141 +/- 26, n=80) whereas women on no medication had lower levels (129 +/- 25, n=99, p is less than 0.01) but men had the lowest levels (120 +/- 20, p is less than 0.01) In a separate group of 14 women given estrogen for 2 wks (1 mug/kg/day), A-I increased by 24%. Thus A-I is increased by exogenous and, most likely, endogenous estrogen, Among hyperlipidemic referral subjects, those with hypercholesterolemia (n=43) and hypertriglyceridemic women (n=33) had normal A-I levels. Among hypertriglyceridemic men both A-I and HDL cholesterol values were decreased (115 +/- 20, p is less than 0.01 and 37 +/- 3, p is less than 0.01, respectively, n=68) but were significantly lower among a group of myocardial infarction survivors (107 +/- 16, p is less than 0.01, and 27 +/- 6, p is less than 0.01, respectively, n=24). High density lipoprotein levels and the content of cholesterol in HDL associated with A-I appear to be decreased in coronary heart disease.
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001059:Apoproteins / Q000032:analysis*; D003278:Contraceptives, Oral, Hormonal / Q000494:pharmacology; D003327:Coronary Disease / Q000097:blood; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood; D006949:Hyperlipidemias / Q000097:blood; D005779:Immunodiffusion; D008075:Lipoproteins, HDL / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood; D012737:Sex Factors; D014280:Triglycerides / Q000097:blood
chemical_list: D001059:Apoproteins; D003278:Contraceptives, Oral, Hormonal; D008075:Lipoproteins, HDL; D014280:Triglycerides