Fig 4.

Heparin (upper panel) and histamine (lower panel) content of rat peritoneal mast cells as a function of number of unit granules per mast cell. ‘Regranulation data’ (indicated by solid diamonds) were derived from rats killed for analysis of peritoneal mast cells by transmission EM 8, 17 or 34 days after the mast cells were induced to degranulate in vivo by four injections (i.p.) of polymyxin B (mg/kg body weight of 2.8 on day 1, 5.7 and days 2 and 3 and 12.0 and day 4). ‘Aging data’ (indicated by solid triangles) were derived from control rats (not injected with mast cell activating agents) killed for analysis of peritoneal mast cells by transmission EM at 1, 2–3 or 5–6 months of age. (Data in upper panel are from [55, 56], with the permission of the publisher: S. Karger, Basel; figure in lower panel is reproduced from [37], with the permission of the publisher.)