Circannual variation in the expression of β2-adrenoceptors on human peripheral mononuclear leukocytes (MNLs)

Abstract

Peripheral mononuclear leukocytes (MNLs) are widely used as a tissue model in studies of β-adrenoceptor disturbances in hypertension and asthmatic diseases. The β₂-adrenoceptor density (B_max), however, depends not only on the gender of the person under study and on the time of day the blood specimens are obtained. Evidence is now reported for a circannual variation in the expression of β₂-adrenoceptor sites on peripheral MNLs. In male volunteers the 24-h mean was found to be highest in the men studied in April/May (1135±10 sites/cell) and decreased to 891±16 sites/cell in August and to 712±90 sites/cell in December (±SE,PP<0.05, April/May compared to December). The circadian acrophase remained constant (190°±30° equivalent to 12 h 40 min±2 h 00 min, ±SE).