Transmucosal potential-difference profile in rat upper gastrointestinal tract. A simple model for testing gastric effects of pharmacologic agents

Transmucosal potential difference in the rat upper gastrointestinal tract is described by a simple in vivo technique. Values for potential difference between blood (reference) and lumen (in millivolts) were the following: esophagus, -13.7 +/- 1.6 (mean +/- SE); forestomach (rumen), -39.2 +/- 0.8; stomach fundus, -39.1 +/- 0.4; pylorus -26.6 +/- 0.6; and duodenum, -9.2 +/- 0.4. These values (excluding rumen) are strikingly similar to those obtained in man. Aspirin, taurocholic acid, and alcohol all produced falls in gastric potential difference very similar to those found in man. The rat appears to be a promising and convenient model for screening gastric effects of certain pharmacological agents before use in man.

Effect of secretin on antipyrine elimination during extracorporeal perfusion of the isolated guinea pig liver

The aim of these investigations was to elucidate in which part of the bile system (canaliculi or ductules) antipyrine is secreted actively into bile during extracorporeal perfusion of isolated guinea pig liver. Twelve perfusions were performed including 6 control and 6 with secretin. After 1, 2 and 3 hours from the onset of perfusion the perfusion fluid and bile samples were taken for determination of antipyrine concentration. It was demonstrated that secretin increases the volume of secreted bile, the concentration of antipyrine was decreased and the total amount of antipyrine eliminated with bile remained unchanged. The obtained results refute the hypothesis that antipyrine is secreted into bile in the ductular phase and suggest that this process takes place at the level of biliary canaliculi.

Effect of glucagon on aspirin-induced gastric mucosal damage in man

The effect of glucagon on aspirin-induced damage to human gastric mucosa and its effect on gastric mucosal potential difference were studied in 27 healthy volunteers. Intragastric instillation of 600 mg of aspirin suspended in 100 ml of isotonic saline caused significant damage to 21 +/- 3% of surface epithelial cells and a marked reduction in gastric potential difference within 15 min of aspirin instillation. Glucagon, 2 mg given intravenously, caused hyperglucagonemia, hypophosphatemia, hyperinsulinemia, increased blood glucose levels and gastric pH, as well as significant prolonged elevation of gastric potential difference. Glucagon injection given 15 min before aspirin instillation effectively prevented surface epithelial cell damage, decreasing percentage of damaged cells to 3.5%. Glucagon did not prevent the drop in gastric potential difference evoked by aspirin, but did, however, prevent potential difference from falling below base line values after aspirin. This study showed in man that glucagon protects gastric mucosa against aspirin damage and suggests possible therapeutic value in clinical situations requiring prevention of aspirin-induced gastric mucosal damage.

Effect of glucagon and radiocalcium excretion by the colon in rats after intracardial administration of 45Ca

After intramuscular administration of glucagon to rats that previously had received 45Ca intracardially, the radioactivity of the colonic fecal content was tenfold lower than that of controls and the radioactivity of the colonic wall was increased moderately.

Effect of calcitonin on the formation, composition, and enzymatic activity of the hepatic bile in guinea pgs

Porcine calcitonin given to guinea pigs in doses causing hypocalcaemia and hypophosphataemia decreased the bilirubin concentration and increased the activity of gamma glutamyl transpeptidase (GGTP) in the hepatic bile. Calcitonin had no effect on bile flow, its pH, electrolyte composition including calcium, or on the concentration of protein, glucose, cholesterol, nonprotein nitrogen (NPN), and bile acids. It also did not affect the activities of alanine aminotransferase (AIAT) and alkaline phosphatase (AP) in the hepatic bile. Calcitonin increased the calcium content in the liver.

Effect of cholecystokinin-pancreozymin and secretin on the volume, composition, and enzymatic activity of hepatic bile in rabbits

In rabbits given cholecystokinin-pancreozymin intravenously a statistically significant increase in bile volume and alkaline phosphatase (AP) activity was observed. There was also an increase in the total amount of protein, cholesterol, bicarbonates Na, K, Ca, Mg, and the total activity of alkaline phosphatase and leucineaminopeptidase (LAP) secreted in bile within 90 minutes after pancreozymin injection. Pancreozymin had no effect on the concentration and output of taurocholates and the activity of gammaglutamyltranspeptidase (GGTP) and alanineaminotransferase (ALAT) in bile. Secretin neither changes the volume nor the concentration of any of the investigated components in rabbit bile.