INTRAGASTRIC NITRIC-OXIDE PRODUCTION IN HUMANS - MEASUREMENTS IN EXPELLED AIR

High values (800-6000 parts per billion) of nitric oxide (NO) in expel led air from the stomach were shown in humans by chemiluminescence tec hnique. These NO values were more than 100 times higher than those fou nd in orally exhaled air. Intragastric NO production is probably non-e nzymatic, requiring an acidic environment, as NO in expelled air was r educed by 95% after pretreatment with the proton pump inhibitor omepra zole. Furthermore, large amounts of NO were formed in vitro from lettu ce and saliva when placed in hydrogen chloride (pH < 2). In conclusion , large amounts of NO are formed intragastrically in humans and this s ource of NO may be of importance for the integrity of the gastric muco sa in health and disease; Measurements of NO in expelled air might be of value as a non-invasive method for estimation of gastric acidity.