Effect of epidermal growth factor on ontogeny of the gastrointestinal tract

The effect of epidermal growth factor (EGF) on the ontogeny of the gastrointestinal tract was examined in New Zealand White rabbits. EGF, 40 micrograms X kg-1 X day-1, was administered to suckling animals from 3-18 days of age either intraperitoneally or orogastrically. Controls received saline. Animals were killed at 17-18 days of age. Body weight and wet weight of stomach, pancreas, and 10-cm segments of proximal, mid, and distal small intestine were measured. The total pancreas was homogenized for determination of protein, DNA, and amylase, and the intestinal mucosa was scraped, weighed, and homogenized for estimation of protein, DNA, sucrase, and lactase. While body weights were similar wet weight of stomach and pancreas were increased by intraperitoneal and orogastric EGF. Small intestinal wet weights were increased in all segments by intraperitoneal but not orogastric EGF, and both routes significantly increased mucosal DNA in the distal segment. EGF administered orogastrically induced precocious maturation of intestinal brush-border disaccharidase activities but had no effect on pancreatic amylase, whereas EGF administered intraperitoneally induced precocious maturation of pancreatic amylase but had no effect on brush-border disaccharidase activities. These findings suggest that both systemic and oral EGF play a role in regulating growth and postnatal maturation of the gastrointestinal tract.