[Influence of fenoterol of cAMP levels and motility on the rat uterus in vitro (author's transl)].

CAMP levels of isolated rat uteri (2nmol/g wwt) were increased by Fenoterol (10(-4)--1 mug/ml) in a dose dependent manner reaching concentrations of more than 10nmol/g withing 2--5 min. AT 2 TIMES 10(-3) MUG/ML Fenoterol inhibited spontaneous contractions of the rat uterus in vitro. A 10,000 fold higher dosis of Fenoterol was needed to elicit a similar degree of inhibition, when contractions were induced by 0.6 mU/ml Oxytocin. However cAMP levels were elevated by Fenoterol in presence of Oxytocin, uterine contractions were not inhibited, i.e. the elevation of cAMP after administration of Fenoterol is correlated with a relaxant effect only in uteri contracting spontaneously.