AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 6 638-G644, Copyright © 1984 by American Physiological Society
Maturational increases and decreases in acid secretion in the rat
S. H. Ackerman and R. D. Shindledecker
We compared basal acid output (BAO) and maximally stimulated acid output
(MAO) in 15-, 30-, and 100-day-old anesthetized rats. At each age we
measured BAO and MAO in response to six different stimuli, pentagastrin
(120 micrograms X kg-1 X h-1), bethanechol (1 mg X kg-1 X h-1), histamine
(8 mg X kg-1 X h-1), the H2-receptor agonist impromidine (0.9 mumol X kg-1
X h-1), hypothermia (30 +/- 2 degrees C core temperature), and pyloric
ligation, and we determined H+ output by continuous perfusion of the
gastric lumen of anesthetized rats. Both weight-adjusted and absolute BAO
were significantly greater in 30-day-old rats than in 15- or 100-day-old
rats. Although 30-day-old rats had only one-fourth the fundic mass of
100-day-old rats, they could secrete two to three times more H+ per hour.
These differences in MAO persisted even after subtracting BAO. Anatomic
data indicate that these age-related changes do not correspond to changes
in mucosal mass or parietal cell mass.
