Influence of Epidermal Growth Factor on the Development of Suckling Mouse Intestinal Mucosa

Abstract

This investigation was undertaken to study the influence of epidermal growth factor on the development of intestinal brush border hydrolytic activities and on the deoxyribonucleic acid synthesis in suckling mice. A premature appearance of sucrase activity was elicited in mice after a single injection of epidermal growth factor at 8 days of age or after one injection per day during 3 days, the level of sucrase activity being dependent of the amount of epidermal growth factor injected (1 or 4 μg body wt · day). Trehalase, glucoamylase, lactase, alkaline phosphatase, and γ-glutamyltranspeptidase activities were increased along the entire small intestine after epidermal growth factor treatment. On the other hand, endoplasmic reticulum membrane-bound glucose-6-phosphatase activity was unaffected by the polypeptide hormone. The effects of a single injection or repeated injections of 4 μg epidermal growth factor/g body wt · day on the deoxyribonucleic acid synthesis in the proximal and distal intestine (sectioned into thirds) as well as in the proximal colon have been determined. While a single injection of epidermal growth factor did not affect the proliferation of the intestinal epithelium, one injection per day during 3 days provoked a significant increase of 3H-thymidine incorporation into deoxyribonucleic acid and a significant enhancement of the mitotic activity. It was concluded that epidermal growth factor is able to influence the maturation and the proliferation of the enterocytes in suckling mouse and that the two phenomena appear to be differentially sensitive to epidermal growth factor in the present conditions.