Regular Diurnal Physiological Variation in Eosinophil Levels in Five Stocks of Mice.

Abstract

Tail blood eosinophil levels were determined under standardized conditions in 4 inbred strains and in one hybrid group of mice at 2 different periods of the day. A low midnight and a high morning level were found in all of the 5 stocks investigated. The differences between the eosinophil count in samples collected between 6-10 a.m. and such obtained between 9 p.m. and 1 a.m. were significant below the 1% level. The data indicate that eosinopenia occurs physiologically in mice which have not been artificially stressed.