AJP - Gastrointestinal and Liver Physiology, Vol 259, Issue 1 108-G115, Copyright © 1990 by American Physiological Society
H(+)-K(+)-ATPase and carbonic anhydrase II gene expression in the developing rat fundus
L. R. Marino, B. H. Muglia and T. Yamada
Department of Pediatrics, University of Michigan Medical Center, Ann Arbor 48109.
H(+)-K(+)-ATPase and carbonic anhydrase II (CA II) are two enzymes that are
involved in the production and secretion of the hydrogen ion by the gastric
parietal cell and maintenance of intracellular pH therein. The present
studies were undertaken to examine whether H(+)-K(+)-ATPase and CA II
expression change in the rat fundus in association with the development of
acid secretory capacity. Changes in enzyme mRNA content in the gastric
fundus of developing rat pups 1-6 wk of age were evaluated using dot blots
and ribonuclease protection assays. In additional studies the localization
of H(+)-K(+)-ATPase and carbonic anhydrase II mRNA was examined by in situ
hybridization in Formalin-fixed gastric tissues from rats 1, 3, 6, and 8 wk
of age. We observed that H(+)-K(+)-ATPase mRNA content increased with age
in the developing rat fundus while CA II mRNA exhibited a reciprocal
decrease. These changes in enzyme mRNA were accompanied by concomitant
changes in the regional distribution of the cells expressing the genes for
the two enzymes. Although the changes in H(+)-K(+)-ATPase mRNA paralleled
the development of acid secretory capacity, CA II mRNA levels might be
regulated by the requirement for maintenance of intracellular pH during
periods of cellular proliferation and by exposure of the gastric surface
epithelium to the highly acidic luminal environment of the stomach.
