AJP - Gastrointestinal and Liver Physiology, Vol 257, Issue 6 851-G859, Copyright © 1989 by American Physiological Society
Effect of epidermal growth factor on the ontogenic response of rat gastric mucosa to H+
B. L. Tepperman and B. D. Soper
Department of Physiology, Faculty of Medicine, University of Western Ontario, London, Canada.
Epidermal growth factor (EGF) plays an important role in the development of
the neonatal intestinal tract and affects the integrity of adult stomach.
This study examined the effects of EGF on the development of mucosal
responses to luminal H+ in rats of various ages. Mucosal response to
luminal acid (300 mN) was measured in rats between 10 and 60 days after
birth. Permeability changes were expressed as H+ loss and Na+, K+, and
protein appearance in the luminal instillate. Losses of H+ and luminal
appearances of Na+, K+, and protein were greater in animals older than 20
days of age compared with younger rats. Mucosal permeability responses to
300 mN HCl were reduced by enteral or parenteral treatment with EGF (5-50
or 10-100 micrograms/kg sc) in rats 20 days of age and older. EGF did not
consistently affect ion and protein fluxes in 10- and 15-day-old rats
treated with HCl. Likewise EGF did not stimulate gastric HCO3- secretion in
any of the age groups examined. Injection of 8-day-old rats with
corticosterone acetate (250 mg/kg) did not affect ion or protein fluxes in
EGF-treated 10-day-old rats. However steroid treatment did result in a
reduction in Na+ and K+ fluxes in 15-day-old rats receiving EGF. EGF was
detected in salivary and duodenal tissue of rats and in the maternal milk
of rat dams.(ABSTRACT TRUNCATED AT 250 WORDS)
