Valosin Stimulates Gastric and Exocrine Pancreatic Secretion and Inhibits Fasting Small Intestinal Myoelectric Activity in the Dog

Abstract

Valosin, a novel 25-amino acid gastrointestinal peptide with N-terminal valine and C-terminal tyrosine, has recently been isolated from porcine upper gut extracts. Its physiologic role is unknown and it does not belong to one of the structurally related gut peptide families. Assuming that valosin may influence gastrointestinal functions, we investigated the effect of high-performance liquid chromatography-pure valosin on gastric and exocrine pancreatic secretion and on the intestinal myoelectric activity in conscious dogs. Intravenous injection of valosin (0.125-1 microgram/kg) dose-dependently increased gastric acid secretion 80-fold over basal, corresponding to 18% of the maximal pentagastrin-induced effect. Pepsin output increased 10-fold over basal (30% of the pentagastrin-stimulated secretion). Half-maximal stimulation by pentagastrin could be further increased dose-dependently by simultaneous administration of valosin. Pancreatic bicarbonate secretion was stimulated 11-fold over basal at 1.0 microgram/kg, reaching about 6% of the secretin-induced maximal output, whereas protein secretion increased 12-fold over basal, corresponding to about 55% of the cholecystokinin-induced maximal output. In fasted dogs, spontaneously occurring migrating myoelectric complexes were substantially delayed during infusion of valosin at a dose of 0.2 microgram/kg. These experiments indicate that valosin may represent a novel member of the regulatory gastrointestinal peptides.