AJP - Gastrointestinal and Liver Physiology, Vol 259, Issue 5 702-G708, Copyright © 1990 by American Physiological Society
Relationship between maternal milk PGE2 and gastric acid secretion in newborn rats
A. Wirbel, R. Ducroc, B. Garzon, C. Merlet-Benichou and J. P. Geloso
Institut National de la Sante et de la Recherche Medicale U319, Universite Paris, France.
We previously demonstrated that in rats gastric acid secretion declines
after birth and drops steeply on day 12 of life. In the present study, we
investigated the part played in this decline by prostaglandin E2 (PGE2)
from maternal milk. PGE2 content was first measured in the milk of
untreated dams 0, 1, 5, 10, 12, 15, and 18 days after parturition. PGE2
levels were high during the first 5 days (123.5-200.5 pg/ml), declined
significantly between days 10 and 15 (56.6-85.4 pg/ml; P less than 0.05),
and dropped to 18.4 pg/ml on day 18. We also found that depleting milk of
PGE2 prevented drop of acid secretion in 12-day-old suckling rats.
Injecting lactating dams with indomethacin significantly reduced milk PGE2
content by 65% vs. milk of untreated dams. Surprisingly, administration of
sesame oil, the indomethacin vehicle to the dams, increased milk PGE2
content by 182%. In the pups of the indomethacin-treated dams, acid
secretion did not drop. On the contrary, in vivo basal and
histamine-induced acid output rose markedly by 40 and 50%, respectively,
and in vitro the net movements of 36Cl and 22Na measured in the isolated
stomach indicated that active Cl- secretion had resumed. Mucosal PGE2 did
not appear to be significantly involved in early development of acid
secretion because administration of indomethacin to pups from untreated
dams did not significantly modify the secretion measured on day 12. Data
indicate that maternal milk depletion of PGE2 prevents the drop of gastric
acid secretion previously observed in 12-day-old pups and suggest that in
infant rats maternal PGE2 plays a physiological part in regulating acid
secretion.
