A Micro-Method for the Study of Acid Secretory Function in Isolated Human Oxyntic Glands from Gastroscopic Biopsies

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Abstract
A method has been developed whereby gastric glands can be obtained from biopsies taken from the human gastric mucosa. Minced pieces of the mucosa incubated with collagenase (1 mg/ml) for 2 h yielded a fraction rich in isolated glands. Shorter incubation with collagenase produced larger chunks of tissue, whereas longer incubation resulted in many free cells which were less responsive to dibutyryl-cAMP and histamine; EM revealed the presence of mucous neck cells, parietal cells, zymogen cells and endocrine cells in the glands. Most of the cells appeared normal, but some of them were vacuolized. Acid secretion in these human glands was determined by the [14C]aminopyrine accumulation technique. Owing to the limited amount of starting material, only a few determinations could be made from each set of biopsies by using the regular macro-method, which normally requires .apprx. 15 mg dry weight of glands per incubation. To overcome this problem a micro-method was developed which permitted the sample size to be scaled down to .apprx. 0.1 mg dry weight; in comparison with the previously used macro-method, the glands assayed by the micro-method seemed less sensitive to the method of shaking during incubation. In the micro-method the glands also seemed more responsive to secretagogues, i.e., histamine or dibutyryl-cAMP produced a 2- to 3-fold increase in [14C]aminopyrine accumulation. The histamine-induced secretion in human glands was effectively inhibited by the histamine H2-receptor antagonist, cimetidine, and that of dibutyryl-cAMP by the substituted benzimidazole, timoprazole. Cholinergic stimulation in the form of carbacholine led to a small and transient response. Thus, human gastric glands, as studied by this micro-method, seem to reveal normal secretory properties. The method may be used to study acid secretory function of gastric glands when human gastric material is restricted, as in the case of gastroscopic biopsies.