Presence of the diurnal rhythms of granulocyte counts and heterophil activities in chicks.

Abstract

The diurnal variations of peripheral granulocyte counts, phagocytic and bacteriocidal activities and superoxide production of peritoneal heterophils were studied in 6 to 12 week-old chicks. It was evident that granulocyte counts and activities of heterophils, i.e., phagocytosis, bateriocidal activity and superoxide production, showed clear diurnal rhythms. The diurnal rhythmic pattern of phagocytic activity was different from and rather opposite to the pattern of granulocyte counts. This means that these rhythmic patterns have no relation and that the low heterophil count was coexistent with high heterophil-phagocytic activity at any given time of day. The rhythmic pattern of heterophilbacteriocidal activity was not in agreement with the pattern of superoxide production. The reason for this is unknown. However, the diurnal rhythmic patterns of bacteriocidal activity and superoxide production are not necessarily the same, since many agents such as oxygen compound other than superoxide, and lysozomal enzymes are known to be involved in intracellular killing of phagocytes.