title: Measurement of meal-stimulated gastric acid secretion by in vivo gastric autotitration.
abstract: Measurement of meal- stimulated gastric acid secretion using manual intragastric titration is demanding in terms of personnel and specialized equipment. In the present study, we used a new method, in vivo gastric autotitration, to determine meal-stimulated gastric acid secretion. Gastric pH was measured every 4 s before, during, and after ingestion of a standard meal in 24 healthy subjects. Placebo, ranitidine (150 mg), ranitidine (75 mg), or famotidine (10 mg) was given 1 h after the beginning of the meal. Meal-stimulated gastric acid secretion was calculated from the amount of HCl required to titrate the homogenized standard meal to pH 2 in vitro (119 mmol) and the time required for the pH of the ingested meal to decrease to pH 2 in vivo. Values for pH were also converted to acid concentration (mM), and integrated acidity was calculated from the cumulative, time-weighted means of the acid concentrations for every fourth second of the postprandial recording period. Control meal-stimulated gastric acid secretion was 60 (40-71) mmol/h (median; interquartile range), and each histamine H(2)-receptor antagonist significantly decreased secretion by approximately 50%. Meal-stimulated acid secretion correlated directly with postprandial integrated gastric acidity (r = 0.72; P = 0.0001). Thus intragastric autotitration is a convenient, reproducible method for measuring gastric acid secretion after ingestion of a solid meal and offers several advantages over manual intragastric titration.
authors.affiliation: Science for Organizations, Inc., Chatham, New Jersey 07928, USA. gardnerj@bellatlantic.net
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Gardner
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Ciociola
authors.forename: Malcolm
authors.initials: M
authors.lastname: Robinson
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000502:physiology*; D015738:Famotidine / Q000494:pharmacology; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D006801:Humans; D006851:Hydrochloric Acid / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008297:Male; D008722:Methods; D019518:Postprandial Period; D011899:Ranitidine / Q000008:administration & dosage / Q000494:pharmacology; D015203:Reproducibility of Results; D017186:Titrimetry / Q000592:standards*
chemical_list: D006635:Histamine H2 Antagonists; D015738:Famotidine; D011899:Ranitidine; D006851:Hydrochloric Acid