STABILITY OF EPIDERMAL GROWTH-FACTOR IN THE GASTROINTESTINAL, LUMEN OF SUCKLING AND WEANED PIGS

The stability of epidermal growth factor (EGF) in the gastrointestinal lumen of 3-day-old suckling and 45-day-old weaned pigs was examined b y incubating iodine labeled recombinant human EGF (hEGF) in the gastro intestinal fluids at 37 degrees C and monitoring the generation of aci d soluble radioactivity. Chromatographic analysis and receptor binding study were also undertaken. The results showed that hEGF was quite st able in the gastric fluids in both suckling and weaned pigs with less than 20% degradation after 20 min incubation. The degradation rate in the intestinal fluids varied with the region of the small intestine an d the age of the animals. At the proximal acid mid regions of the smal l intestine in suckling pigs the degradation rate of hEGF after 20 min incubation was 5 and 20% respectively, while the degradation rate at the distal region was up to 50%. In the small intestinal lumen in wean ed pigs the degradation rate of hEGF was much greater than that in suc kling pigs, and the degradation rates at the proximal, mid and distal regions were 33, 51 and 55% respectively. Addition of acid soluble or casein fractions of porcine colostrum markedly reduced the degradation of hEGF in the intestinal fluids. These results indicate that milk-bo rne EGF is stable in the gastric and proximal intestinal lumen in suck ling pigs, and may play a role in regulating postnatal development in the suckling young.