Adenylyl cyclase activity in human decidua and myometrium during pregnancy and labour.

Adenylyl cyclase activity was studied in human decidua and myometrium in early pregnancy and at term before and after the onset of labour. Decidual basal, prostaglandin-, catecholamine- and forskolin-stimulated adenylyl cyclase activities at term before the onset of labour were significantly lower than those in early pregnancy. After the onset of labour at term, decidual basal, prostaglandin-, catecholamine-, NaF- and forskolin-stimulated adenylyl cyclase activities significantly increased compared with those at term before the onset of labour. Myometrial prostaglandin- and catecholamine-stimulated activities did not alter during pregnancy, except for basal and forskolin-stimulated activity. Myometrial basal, prostaglandin-, catecholamine-, NaF- and forskolin-stimulated activities at term showed no change after the onset of labour. At term, before the onset of labour, myometrial basal, prostaglandin, catecholamine-, NaF- and forskolin-stimulated activities were the same as those in the decidua. However, after the onset of labour at term, decidual basal and the stimulated activities were significantly higher than those in the myometrium. These results suggest that decidual prostaglandin- and catecholamine-stimulated adenylyl cyclase may play an important role in the initiation or maintenance of human labour or in both processes.