Cysteamine-induced duodenal ulcer: effects on calcium absorption across rat duodenum.

Abstract 1. 1. The effect of cysteamine-induced duodenal ulcers on calcium transport across rat duodenum was investigated. 2. 2. Intracellular calcium accumulation measured after 24 hr and 3 days of cysteamine injection showed a significant increase ( P 3. 3. The relationship between increasing calcium concentration in the incubation medium and intracellular calcium concentration is a saturable process that conforms to the Michaelis-Menten type of kinetics. 4. 4. The average maximal flux ( V max ) increased from 8.93 nmole/hr-gdw in normal to 12.5 nmole/hr-gdw in 3-day-ulcerated rats, with no apparent change in the Michaelis constant ( K t ) (0.8 mM). 5. 5. Unidirectional influx of calcium across the mucosal membrane was significantly increased ( P