Influence of diet on the development of antral gastrin-like immunoreactivity in the stomach of rats.

The effects of individual food constituents on antral gastrin-like immunoreactivity concentrations were studied in young rats. Rats aged 7 to 20 days were given only rat breast milk and then weaned by various nutrients (regular laboratory chow, protein (ovalbumin)-, fat- or carbohydrate (starch)-rich food). Rats receiving rat breast milk only until 27 days of age were also studied. In rats on regular laboratory chow, antral gastrin-like immunoreactivity increased and reached adult levels on day 25. In rats on ovalbumin, fat-rich food or starch, it increased on day 23 but dropped thereafter. The increment by laboratory chow was higher than that by the individual nutrients. No increase was observed during milk feeding alone. Gel filtration of antral gastrin-like immunoreactivity from 25-day-old rats on laboratory chow or three essential nutrients showed the same results.