Effect of Horse Serum, Adrenal Hormones, and Histamine on the Number of Eosinophils in the Blood and Peritoneal Fluid of Mice

A technic of performing reliable eosinophil determinations on the peritoneal fluid of mice is described. This procedure was found to be rapid and did not necessitate killing the animals.

Simultaneous determinations of the blood and peritoneal eosinophils were made at 3 hour intervals throughout a 24 hour period. A marked diurnal rhythm was found in the blood eosinophils, but little change occurred in the number of eosinophils found in the peritoneal cavity.

During a period of 3 hours following stress, there was a marked blood eosinopenia, but little or no change in the peritoneal eosinophils. Repeated intraperitoneal injections of 0.1 ml. normal horse serum resulted in a great increase in the number of peritoneal eosinophils. These cells appeared to be morphologically identical with the blood eosinophils. In mice which were pretreated with horse serum, relatively large injections of cortisone, compound F, epinephrine and histamine produced a marked blood eosinopenia, but failed to reduce the number of peritoneal eosinophils within 3 hours. The response of eosinophils in blood and peritoneal fluid to cortisone was essentially the same either when it was injected subcutaneously or intraperitoneally.

Implantations of pellets of cortisone acetate in the peritoneal cavity produced a blood eosinopenia beginning within 1 hour and reaching a maximum at approximately 3 hours. The peritoneal eosinophils did not begin to drop until approximately 6 to 10 hours after the implantation.

These data were interpreted as indicating that physiologic doses of cortisone, compound F, epinephrine or histamine do not have a direct lytic action upon the eosinophils of mice.