CIRCADIAN-RHYTHM OF LEUKOCYTES AND LYMPHOCYTE SUBSETS AND ITS POSSIBLE CORRELATION WITH THE FUNCTION OF THE AUTONOMIC NERVOUS-SYSTEM

There are physiological variations in the levels of leucocytes. Among these, the circadian rhythm is very important in terms of the magnitud e. Since newly identified lymphocyte subsets (i.e. extrathymic T cells ) have recently been detected, a comprehensive study of the circadian rhythm was conducted. All leucocytes were found to vary in number or p roportion with a circadian rhythm and were classified into two groups. One group--granulocytes, macrophages, natural killer (NK) cells, extr athymic T cells, gamma delta T cells, and CD8(+) subset--showed an inc rease in the daytime (i.e. daytime rhythm). The other group-T cells, B cells, alpha beta T cells, and CD4(+) subset--showed an increase at n ight. Humans are active and show sympathetic nerve dominance in the da ytime. Interestingly, granulocytes and lymphocyte subsets with the day time rhythm were found to carry a high density of adrenergic receptors . On the other hand, lymphocyte subsets with the night rhythm carried a high proportion of cholinergic receptors. Reflecting this situation, exercise prominently increased the number of cells with the daytime r hythm. These results suggest that the levels of leucocytes may be unde r the regulation of the autonomic nervous system.