A method for in vitro studies on acid formation in human parietal cells. Stimulation by histamine, pentagastrin and carbachol.

Cells were isolated from human gastric mucosa on a large scale from gastric resection specimens and on a microscale from endoscopic biopsies by sequential incubations with pronase and collagenase. The accumulation of aminopyrine (AP) was used as an index of acid production in the parietal cells. Basal accumulation was about 0.2 pmol AP/10(4) parietal cells. Addition of histamine, db-cAMP, pentagastrin and carbachol increased the aminopyrine accumulation. Maximal accumulation was of the order of 1000-2800% of the control and was obtained after stimulation by 10(-4) M histamine and by 10(-3) M db-cAMP. Stimulation by pentagastrin and by carbachol reached 200 to 350% of the control. EC50 was 2 X 10(-6) M for histamine, 10(-8) M for pentagastrin, and 4 X 10(-6) M for carbachol. Human parietal cells were enriched from a mixture of gastric mucosal cells by isopycnic centrifugation on density gradients of Percoll. A parietal cell fraction with a purity of 83% was obtained. The density of human parietal cells was estimated to 1.06 g . ml-1.