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The metabolism of [14C]histamine during pentagastrin‐stimulated acid secretion in the cat.
Author(s) -
Bunce K T,
Lake H J
Publication year - 1978
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1978.sp012390
Subject(s) - pentagastrin , histamine , secretion , medicine , metabolite , gastric acid , endocrinology , chemistry , gastric mucosa , metabolism , urine , stimulation , gastrin , stomach , biochemistry , biology
1. The metabolism of exogenous [14C]histamine has been examined in cats during gastric secretion. The appearance of 14C‐labelled metabolites has been measured chromatographically in urine and gastric juice under non‐secreting and pentagastrin‐stimulated conditions, and in gastric mucosa after pentagastrin stimulation. 2. The main metabolites detected were (i) an acidic product, presumed to be methylimidazoleacetic acid, (ii) Ntau‐methylhistamine, and (iii) an unidentified metabolite, moving rapidly in the chromatographic systems used, and designated 'preacetylhistamine'. No evidence was found for the presence of side chain (i.e. Nalpha)‐methylated histamines, either in the non‐stimulated or pentagastric‐stimulated state. 3. During a 3 hr non‐stimulated period, followed by 3 hr of pentagastrin administration, the relative proportions of 14C‐labelled metabolites excreted in urine remained unchanged. During acid secretion there was an increase in the proportion of 'pre‐acetylhistamine' in gastric juice, which occurred at the expense of the acidic metabolites. It is suggested however that this effect is more likely to be the result of a slow adaptation to the administration of exogenous [14C]histamine than the result of acid secretion. 4. The results of the present work do not appear to support the hypothesis of Code (1970), that a local control mechanism for acid secretion might involve the formation Nalpha‐methylated histamine metabolites in gastric mucosa.