Separation and characteristics of two histaminocytes from rat gastric mucosa.

To determine the properties of rat gastric cells involved in histamine metabolism (histaminocytes), fundic mucosa was enzymatically dispersed prior to separation by sedimentation methods. The distribution of histamine content, histidine decarboxylase (HDC) activity and incorporation of radioactive histidine metabolites were used to determine the characteristics of various populations of gastric cells. All activities measured, as well as most of the dispersed gastric cells, occurred in a narrow range of density between 1.083 and 1.091 g/ml. Velocity sedimentation showed that two populations of histaminocytes can be distinguished. One population has a higher sedimentation rate, suggesting a larger size, contains histamine, HDC activity and incorporates radioactive metabolites. Another population, in fractions with lower sedimentation rates, contains little histamine, has a higher HDC activity than the previous population and also incorporates radiolabelled histidine metabolites. For the first time, two populations of viable histaminocytes have been separated that differ in their biochemical properties.