615 EGF-MEDIATED BREAST MILK-ENHANCED INTESTINAL GROWTH IN NEONATAL RATS

We recently showed that newborn rats handfed rat breast milk for 40 hours demonstrated greater intestinal growth than animals handfed an isocaloric formula. (Clin Res 31: A132, 1983) It was postulated that Epidermal Growth Factor (EGF) present in rat breast milk may be partly responsible for mediating this trophic response. 87 neonatal rats who never suckled were fed artificial formula containing 0, 1.2, 3.0, or 6.0 mcg/ml EGF for 40 hours. All 4 groups of rats gained weight by 40 hours, but there were no differences in whole body weight among the groups. Animals fed 3.0 and 6.0 mcg/ml of EGF-supplemented formula had significantly heavier whole intestines (p<.05 and p<.01, respectively); however, there were no significant differences in stomach or liver weight. Rats fed formula containing 3.0 and 6.0 mcg/ml EGF demonstrated significantly greater incorporation of 3H Thymidine into DNA in the proximal (p<.01) and distal bowel (p<.01) compared to animals fed 0 EGF. Additionally, animals fed 3.0 and 6.0 mcg/ml EGF had greater intestinal DNA content (p<.05).Ten newborn rats were fed breast milk containing rabbit-derived EGF antibody for 40 hours. The intestines of these pups were lighter (p<.001) and contained less DNA (p<.05) than the intestines of 10 newborn rats fed breast milk without antibody. These data indicate that EGF may in part mediate breast milk-enhanced intestinal growth in the newborn rat.