Aging and gastrin production: changes in serum and antral gastrin concentrations in the rat.

Serum gastrin concentration and antral gastrin content were measured in 4-5- and 26-28-mo rats under fed conditions, after 3 days of starvation, and after 1 day of refeeding after starvation, to determine whether gastrin homeostasis is altered during aging. Gastric weight was 29% greater, but antral weight and DNA were less in the older rats. Serum gastrin fell during starvation and rose during refeeding in both groups, but it was lower in aging rats only during refeeding. Antral gastrin content in older animals was 60% of that in young rats. Starvation reduced antral gastrin only in the young, whereas refeeding lowered antral gastrin in the older animals. We conclude that, in aging rats, the relationship of serum and antral gastrin is altered during changes in food intake.