Electron microscopic study of the regeneration in vivo of rat peritoneal mast cells after histamine secretion.

Peritoneal mast cells regenerate their histamine granules in 5-6 weeks after intraperitoneal injection of the degranulating agent compound 48/80. In the beginning of the regeneration the small exocytic cavities containing the non-secreted granule remnants coalesce to a single large cavity. Later on this cavity decreases in size and becomes a small vacuole containing a very condensed material. After two weeks of regeneration mast cells are already capable of another secretory event.