In the rat, two distinct mast cell subsets have been identified. One, represented by the easily accessible and purified peritoneal mast cell, differs from the other, the intestinal mucosal mast cell, in staining properties, fixation sensitivity, mediator content, and responsiveness to various secretagogues and antiallergic drugs. To investigate the molecular basis and control mechanisms of mast cell heterogeneity, we have (a) initiated sodium dodecylsulfate polyacrylamide gel electrophoretic analysis of the constituents of rat peritoneal and intestinal mucosal mast cells; (b) developed subcellular fractionation protocols to facilitate these comparisons; (c) produced a mast cell specific rabbit antiserum, and (d) established methods to isolate mast cell RNA. These approaches require refinement, but will prove to be useful in further investigations of mast cell biology.
