[Biochemical requirements in tocolysis]

By a specific bond of 3H-dihydroalprenolol the number (Bmax) and characteristic (Kd) of sympathetic beta-receptors in cell membranes of the myometrium and lymphocytes of peripheral blood was assessed. The authors examined six tissue specimens taken during planned termination of pregnancy during the 38th-40th week by primary Caesarean section parallel with a peripheral blood sample. In healthy women even at the end of pregnancy the myometrium contains ample amounts of specific beta-receptors. As compared with the myometrium, the lymphocytes of the peripheral blood contain beta-adrenergic receptors of the same type as the myometrium but in much smaller amounts. So far it was not possible to show a correlation between the number of sympathetic beta-receptors in the membranes of the myometrium and of lymphocytes in the peripheral blood.