Abstract
Intravenous infusion of buphenine hydrochloride was admistered on 4 successive days to 8 pregnant women with imminent preterm labor. Serial blood samples taken before and throughout the study were assayed for lymphocyte β2-adrenoceptor density and cyclic adenosine-3′,5′-monophosphate (cAMP). The lymphocyte β2-adrenoceptor density declined significantly (p<0.01) during the treatment. The plasma cAMP concentration was highest 4 h after commencement of infusion and decreased thereafter. Despite the decrease in lymphocyte β2-adrenoceptor density, the clinical response remained good and the parturients did not go into labor until several days after infusion was started.