Low levels of apolipoprotein A1 are not contributors to the low lecithin-cholesterol acyl transferase activity in premature newborn infants.
Umbilical cord sera were obtained from three groups of newborn infants; group I (n = 8) and group II (n = 12) weighed less than 1500 g and between 1500 and 2500 g, respectively. Group III (n = 16) was full term and weighed more than 2500 g. Lecithin-cholesterol acyl transferase activities, determined as the rates of esterification of [3H]cholesterol, were 0.13 +/- 0.01, 0.17 +/- 0.01, and 0.26 +/- 0.01 (mean +/- SEM) nmol/h/ml for groups I, II, and III, respectively. The adult value (n = 8) was 0.96 +/- 0.01 nmol/h/ml. The respective apolipoprotein A1 (apo-A1) levels were 52 +/- 6, 59 +/- 4, and 67 +/- 4 (mean +/- SEM) mg/dl. Serum level of apo-A1 in adults was 137 +/- 6 mg/dl. Plasma high-density lipoprotein cholesterol levels increased with gestational age. However, in newborn infants, high-density lipoprotein apo-lipoprotein B, total cholesterol, and triglyceride levels, were significantly lower than in adults. These data indicate that serum levels of lecithin-cholesterol acyl transferase activity significantly (p less than 0.01) increase whereas the levels of apo-A1 do not significantly change with the gestational age. Also, in full-term newborns, lecithin-cholesterol acyl transferase activity is only 27%, whereas apo-A1 levels are 49% of adult values. Therefore, lower levels of apo-A1 do not account for the significantly lower activity of lecithin-cholesterol acyl transferase in preterm as compared to full-term newborn infants.
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Department of Pediatrics, Georgetown University Medical Center, Washington, D.C. 20007.
Chowdhry
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Hamosh
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Hamosh
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D001054:Apolipoproteins A / Q000097:blood*; D001055:Apolipoproteins B / Q000097:blood; D001724:Birth Weight; D002784:Cholesterol / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D005260:Female; D005312:Fetal Blood / Q000032:analysis / Q000201:enzymology*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000097:blood*; D007234:Infant, Premature / Q000097:blood*; D008297:Male; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000097:blood*; D014280:Triglycerides / Q000097:blood
D001054:Apolipoproteins A; D001055:Apolipoproteins B; D008076:Cholesterol, HDL; D014280:Triglycerides; D002784:Cholesterol; D007862:Phosphatidylcholine-Sterol O-Acyltransferase