The aim of this study was to determine serum lecithin: cholesterol acyltransferase (LCAT) activity in parallel with HDL2 and HDL3 composition in cord sera of small for gestational age (SGA) newborns, and to compare them with those obtained from appropriate for gestational age (AGA) newborns. LCAT activity was assayed by conversion of [3H]cholesterol to labelled cholesteryl ester. HDL2 and HDL3 were separated by ultracentrifugation. Serum cholesteryl ester, apolipoprotein (apo) A-I concentrations and LCAT activity were significantly lower (-47%, -18% and -56%, respectively), whereas serum triglyceride amounts were twofold higher in SGA newborns than in AGA newborns. In SGA newborns, HDL2 and HDL3 levels were low, and HDL3 and HDL2 phospholipid and HDL2-cholesteryl ester contents were diminished. HDL3-apo A-I, A-II, C-III and E values were lower in SGA newborns. In HDL2, apo A-I, A-II and E concentrations were decreased. Therefore, in SGA newborns, the reduced LCAT activity was associated with quantitative and qualitative changes in HDL2 and HDL3 particles.

Our earlier studies (Meghelli-Bouchenak et al, 1987, 1989a Knipping (1986).In the T group (15% casein), a reduction in LACT activity with age was noted. The onset of both types of PM promoted the same significant decrease in LCAT activity (P < 0.05). At d 3 of BR, a significant rise was observed, which was more marked in group C (2% casein) than in group Gi (5% gluten).This study confirmed that HDL were resistant to PM and that their apoprotein and lipid composition was not significantly modified. Balanced refeeding involved a significant increase in apo AI. These results suggest that in spite of the reduction in LACT activity with both types of PM, HDL metabolism was not significantly impaired, this was due in part to a normal level of apo Al.