1. Intracellular concentrations of adenosine 3′: 5′-cyclic phosphate (cyclic AMP) and activities of adenylcyclase and phosphodiesterase were determined in oestrogen-pretreated rat uteri during exposure to different concentrations of angiotensin II.
2. No significant variations in cyclic AMP or in the enzyme activities were observed at concentrations of angiotensin inducing significant contractions.
3. It is concluded that in rat uterus, the process of excitation-contraction coupling triggered by angiotensin is not mediated by variations in intracellular levels of cyclic AMP.