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Title: Amiloride inhibits rat mucosal ornithine decarboxylase activity and DNA synthesis

Abstract

Refeeding fasted rats induces a dramatic trophic response in gastrointestinal mucosa and is associated with elevations in both rate of DNA synthesis and ornithine decarboxylase (ODC) activity. The signal for these increases is unknown. Amiloride prevents cell alkalinization by blocking Na{sup +}-H{sup +} exchange at apical epithelial cell membranes. In study 1, rats were fasted 48 h, treated with amiloride (0.5 to 500 mg/kg), and refed for 4 h. Refeeding increased ODC activities in the jejunal mucosa (X8) and liver (X19) but not in the oxyntic gland mucosa. In the jejunum, but not the liver, the activation of ODC was completely abolished by 100 mg/kg amiloride. In study 2, the rate of DNA synthesis was determine by measuring the rate of ({sup 3}H)thymidine incorporation 16 h after refeeding. Refeeding resulted in significantly increased rates of DNA synthesis over fasted levels, and amiloride at 100 mg/kg significantly reduced the elevations in the jejenum and liver. In conclusion, amiloride inhibits the postprandial increases in jejunal ODC activity and DNA synthesis in the jejunum and liver. The results indicate that (1) the Na{sup +}-H{sup +} antiport is essential to the increased ODC activity in the jejunum and liver after a meal and (2)more » increases in DNA synthesis and their suppression by amiloride are not necessary linked to ODC activity.« less

Authors:
; ; ;  [1]
  1. Univ. of Texas Health Science Center, Houston (USA)
Publication Date:
OSTI Identifier:
6948754
Resource Type:
Journal Article
Journal Name:
American Journal of Physiology; (USA)
Additional Journal Information:
Journal Volume: 254:3; Journal ID: ISSN 0002-9513
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; DECARBOXYLASES; INHIBITION; DIURETICS; BIOLOGICAL EFFECTS; DNA REPLICATION; IONS; INTESTINAL ABSORPTION; CELL MEMBRANES; EPITHELIUM; FASTING; LIVER; MUCOUS MEMBRANES; ORNITHINE; PH VALUE; PROTONS; SMALL INTESTINE; SODIUM COMPOUNDS; THYMIDINE; TRITIUM COMPOUNDS; ABSORPTION; ALKALI METAL COMPOUNDS; AMINO ACIDS; ANIMAL TISSUES; AZINES; BARYONS; BODY; CARBON-CARBON LYASES; CARBOXY-LYASES; CARBOXYLIC ACIDS; CELL CONSTITUENTS; CHARGED PARTICLES; DIGESTIVE SYSTEM; DRUGS; ELEMENTARY PARTICLES; ENZYMES; FERMIONS; GASTROINTESTINAL TRACT; GLANDS; HADRONS; HETEROCYCLIC COMPOUNDS; HYDROGEN COMPOUNDS; INTESTINES; LYASES; MEMBRANES; NUCLEIC ACID REPLICATION; NUCLEONS; NUCLEOSIDES; NUCLEOTIDES; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORGANS; PYRIMIDINES; RIBOSIDES; TISSUES; UPTAKE; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Ulrich-Baker, M G, Wang, P, Fitzpatrick, L, and Johnson, L R. Amiloride inhibits rat mucosal ornithine decarboxylase activity and DNA synthesis. United States: N. p., 1988. Web.
Ulrich-Baker, M G, Wang, P, Fitzpatrick, L, & Johnson, L R. Amiloride inhibits rat mucosal ornithine decarboxylase activity and DNA synthesis. United States.
Ulrich-Baker, M G, Wang, P, Fitzpatrick, L, and Johnson, L R. 1988. "Amiloride inhibits rat mucosal ornithine decarboxylase activity and DNA synthesis". United States.
@article{osti_6948754,
title = {Amiloride inhibits rat mucosal ornithine decarboxylase activity and DNA synthesis},
author = {Ulrich-Baker, M G and Wang, P and Fitzpatrick, L and Johnson, L R},
abstractNote = {Refeeding fasted rats induces a dramatic trophic response in gastrointestinal mucosa and is associated with elevations in both rate of DNA synthesis and ornithine decarboxylase (ODC) activity. The signal for these increases is unknown. Amiloride prevents cell alkalinization by blocking Na{sup +}-H{sup +} exchange at apical epithelial cell membranes. In study 1, rats were fasted 48 h, treated with amiloride (0.5 to 500 mg/kg), and refed for 4 h. Refeeding increased ODC activities in the jejunal mucosa (X8) and liver (X19) but not in the oxyntic gland mucosa. In the jejunum, but not the liver, the activation of ODC was completely abolished by 100 mg/kg amiloride. In study 2, the rate of DNA synthesis was determine by measuring the rate of ({sup 3}H)thymidine incorporation 16 h after refeeding. Refeeding resulted in significantly increased rates of DNA synthesis over fasted levels, and amiloride at 100 mg/kg significantly reduced the elevations in the jejenum and liver. In conclusion, amiloride inhibits the postprandial increases in jejunal ODC activity and DNA synthesis in the jejunum and liver. The results indicate that (1) the Na{sup +}-H{sup +} antiport is essential to the increased ODC activity in the jejunum and liver after a meal and (2) increases in DNA synthesis and their suppression by amiloride are not necessary linked to ODC activity.},
doi = {},
url = {https://www.osti.gov/biblio/6948754}, journal = {American Journal of Physiology; (USA)},
issn = {0002-9513},
number = ,
volume = 254:3,
place = {United States},
year = {Tue Mar 01 00:00:00 EST 1988},
month = {Tue Mar 01 00:00:00 EST 1988}
}