Amiloride inhibits rat mucosal ornithine decarboxylase activity and DNA synthesis
- Univ. of Texas Health Science Center, Houston (USA)
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.
- OSTI ID:
- 6948754
- Journal Information:
- American Journal of Physiology; (USA), Vol. 254:3; ISSN 0002-9513
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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