Stomach remodeling-associated changes of H+/K+-ATPase ? subunit expression inXenopus laevis and H+/K+-ATPase-dependent acid secretion in tadpole stomach
✍ Scribed by Ikuzawa, Masayuki ;Yasumasu, Shigeki ;Kobayashi, Ken-Ichiro ;Inokuchi, Tomofumi ;Iuchi, Ichiro
- Book ID
- 102337239
- Publisher
- John Wiley and Sons
- Year
- 2004
- Tongue
- English
- Weight
- 467 KB
- Volume
- 301A
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
Through subtractive hybridization, H^+^/K^+^‐ATPase β subunit mRNA, highly expressed in the larval stomach of Xenopus laevis, was isolated. In situ hybridization demonstrated that the H^+^/K^+^‐ATPase β subunit mRNA was exclusively expressed in manicotto gland cells of the larval stomach, not in any other cell. Northern blot analysis showed that metamorphosis‐associated changes of the H^+^/K^+^‐ATPase β subunit mRNA expression in the stomach were characterized by high expression in tadpoles, a considerably lower expression in metamorphosing tadpoles, and a re‐increase of expression in froglets. Further in situ hybridization showed that the decrease of expression correlated with the degeneration of larval type epithelium in the manicotto gland, while the re‐increase correlated with the differentiation of oxynticopeptic cells of the adult type stomach. Moreover, the H^+^/K^+^‐ATPase β subunit mRNA was expressed in adult epithelial primordia. Such changes were found in thyroid hormone‐induced precocious metamorphosis. Based on studies using this ATPase as well as xP1 and PgC (pepsinogen C) as molecular markers, this study discusses a probable cell lineage involved in metamorphosis‐associated stomach remodeling. The pH of luminal contents of the larval stomach was found to be lower than 2. In addition, the pH of an isolated stomach changed from 7.2 to lower than 4 after incubation in Ringer's solution, suggesting acid production from the larval stomach. This is the first demonstration of the H^+^/K^+^‐ATPase‐mediated acid production and secretion in the larval stomach of Xenopus laevis. J. Exp. Zool. 301A:992–1002, 2004. © 2004 Wiley‐Liss, Inc.