[Interrelation of diurnal rhythms of recirculation of lymphocytes and their synthesis of cAMP]

The correlative analysis of diurnal rhythms of cell number and adenylate cyclase cellular activity was performed in the thymus, spleen and peripheral blood of Swiss mice, intact or thymectomized at the age of 3 months. The existence of somehow synchronized diurnal rhythms of cAMP exchange and cell recirculation was found in the peripheral lymphocyte pool and in the thymus. Diurnal rhythm of cAMP synthesis in peripheral lymphocytes was regulated by the thymus. Thymectomy led to desynchronization of recirculating processes and cyclic nucleotide metabolism in immunocompetent cells.