Does pretreatment with omeprazole reduce intragastric nitric oxide production in humans?
Large amounts of NO are formed intragastrically in humans, likely non-enzymatically in an acidic environment, and can be measured in expelled air as a potential non-invasive method for estimating gastric acidity.
High values (800-6000 parts per billion) of nitric oxide (NO) in expelled air from the stomach were shown in humans by chemiluminescence technique. These NO values were more than 100 times higher than those found in orally exhaled air. Intragastric NO production is probably non-enzymatic, requiring an acidic environment, as NO in expelled air was reduced by 95% after pretreatment with the proton pump inhibitor omeprazole. Furthermore, large amounts of NO were formed in vitro from lettuce and saliva when placed in hydrogen chloride (pH < 2). In conclusion, large amounts of NO are formed intragastrically in humans and this source of NO may be of importance for the integrity of the gastric mucosa in health and disease. Measurements of NO in expelled air might be of value as a non-invasive method for estimation of gastric acidity.
Lundberg et al. (Tue,) studied this question.