INFLUENCE OF AGING ON GASTRIC-EMPTYING OF LIQUIDS, SMALL-INTESTINE TRANSIT, AND FECAL OUTPUT IN RATS

The gastric emptying of a liquid meal, the small bowel transit, and th e number of pellets and fecal output produced during a 24-h period, we re studied in young (three months), adult (12 months) and old (24 mont hs) male Wistar rats. The gastric emptying after 20 min of an intragas trically administered liquid meal containing phenol red and methylcell ulose was significantly decreased in old rats. The small bowel transit after 15 and 30 min of the front of a charcoal and Arabic gum contain ing intragastrically administered meal was similar in the three age gr oups. The number of pellets and the mass of the feces produced during a 24-h period were significantly decreased with age, while the food in take was similar. The water content of the pellets was similar in the three age groups. These results show decreased gastric emptying of liq uids and decreased stool mass in old rats, corresponding with the prev iously reported age-related changes in colonic smooth muscle contracti lity. Small intestinal transit was well maintained with age.