A method for the bioassay of intestinal secretory activity in the conscious rat: studies with arachidonic acid and prostaglandin E2.
A method to study the kinetics of intestinal absorption and secretion in the unanesthetized rat is described. This procedure consists of the perfusion of the small intestine with isotonic NaCl-KCl-[36Cl]NaCl and polyethylene glycol-6000 as a nonabsorbable marker. Secretagogues [arachidonic acid (AA) or PGE2] were administered by continuous infusion via the superior mesenteric artery. Samples of perfusate, taken every 15 min, were analyzed for Na, Cl, 36Cl, K, and PEG-6000 to calculate solute and volume movement. In control rats, net absorption of water and electrolytes increased steadily throughout the 2-hr duration of the perfusion. Water, Na, and Cl moved across the intestine in parallel proportions. Net absorption of K was lower than that of the other electrolytes. AA, at the intraarterial dose of 1 mg/kg/hr did not produce a significant effect; at 4 mg/kg/hr it impaired net absorption, and at 8 mg/kg/hr it gradually enhanced net secretion of both water and electrolytes, especially K. Secretion was also demonstrated with the intraarterial infusion of PGE2 (312 microgram/kg). It is concluded that this new rat model is suitable for the bioassay of intestinal secretory stimulants and can be used for the search of intestinal antisecretory drugs.
D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology*; D001692:Biological Transport; D003243:Consciousness; D015232:Dinoprostone; D004573:Electrolytes / Q000378:metabolism; D005260:Female; D007261:Infusions, Intra-Arterial; D007408:Intestinal Absorption / Q000187:drug effects*; D007419:Intestinal Secretions / Q000187:drug effects* / Q000502:physiology*; D007421:Intestine, Small / Q000502:physiology*; D010477:Perfusion; D011458:Prostaglandins E / Q000494:pharmacology*; D051381:Rats; D014867:Water / Q000378:metabolism
D001095:Arachidonic Acids; D004573:Electrolytes; D011458:Prostaglandins E; D014867:Water; D015232:Dinoprostone