Radioimmunoassay of human plasma lecithin-cholesterol acyltransferase

J Clin Invest. 1981 Jan;67(1):141-8. doi: 10.1172/JCI110006.

Abstract

A sensitive and precise competitive-displacement double-antibody radioimmunoassay was developed for the human plasma enzyme lecithin-cholesterol acyltransferase (LCAT; Ec 2.3 1.43). The ability of plasma from various animal species to displace labeled human LCAT from goat anti-human LCAT could be ranked in the following order: man and sheep > nonhuman primates > cat or dog > pig > rabbit or guinea pig > mouse > rat. Normolipidemic subjects had levels of LCAT of 6.14 +/- 0.98 micrograms/ml (mean +/- SD, n = 66). Subjects with dysbeta-lipoproteinemia had the highest plasma LCAT levels (7.88 +/- 0.39 micrograms/ml, n = 7, P < 0.05), followed by hypercholesterolemic subjects (7.00 +/- 1.30, n = 41) and hypertriglyceridemic subjects (6.96 +/- 1.3, n = 10). LCAT-deficient subjects had the lowest enzyme levels (0.89, 0.83, and 0.05 micrograms/ml, respectively, and two subjects with no detectable enzyme). Males had lower LCAT levels (6.42 +/- 1.05 micrograms/ml, n = 90, for all subjects; 5.99 +/- 1.03, n = 44, for normolipidemics) than females (7.01 +/- 1.14, n = 34, for all subjects P < 0.01; 6.44 +/- 0.79, n = 22, for normolipidemics, P < 0.01). LCAT levels correlated significantly with total cholesterol (males, r = 0.384, P < 0.001; females, r = 0.519, P < 0.002); and total triglyceride (only in females, r = 0.512, P < 0.002). LCAT levels in females correlated inversely with HDL cholesterol (r = 0.341, P < 0.05) and apoprotein D (r = 0.443, P < 0.02), but no such relationship existed in males.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blood Preservation
  • Blood Proteins / analysis
  • Female
  • Freezing
  • Haplorhini / blood
  • Humans
  • Hyperlipidemias / enzymology
  • Lecithin Cholesterol Acyltransferase Deficiency / enzymology
  • Lipids / blood
  • Male
  • Phosphatidylcholine-Sterol O-Acyltransferase / blood*
  • Plasma / enzymology
  • Radioimmunoassay
  • Sheep / blood

Substances

  • Blood Proteins
  • Lipids
  • Phosphatidylcholine-Sterol O-Acyltransferase