INFLUENCE OF BREAST AND FORMULA FEEDING ON HEPATIC CONCENTRATIONS OF APOLIPOPROTEIN AND LOW-DENSITY-LIPOPROTEIN RECEPTOR MESSENGER-RNAS

We tested the hypothesis that breast and formula feeding differentiall y affect hepatic mRNA concentrations for LDL receptor (LDL-R) and apol ipoproteins A-I, B and E in infant baboons during the preweaning perio d. The mRNA concentrations were measured in liver biopsies obtained pr ior to weaning at 14 weeks from 43 baboons that were either breast-fed (n = 17) or fed formulas with a high (n = 12) or low (n = 14) polyuns aturated/saturated (P: S) fat ratio. Breast-fed baboons had 99% higher LDL-R mRNA concentrations compared with infants fed formulas, but the re were no differences among breast and formula-fed baboons in mRNA co ncentrations of apolipoproteins A-I, B or E. The fatty acid P: S ratio of the formulas did not affect hepatic LDL-R or apolipoprotein mRNA c oncentrations. These results suggest that breast-feeding increases LDL -R gene expression even though breast milk is higher in cholesterol an d saturated fat compared with formulas.