Effect of prostaglandins and epinephrine on the level of cyclic AMP- 14C of smooth muscle from the rhesus monkey

Abstract

The effects of prostaglandins (PG) and epinephrine on the level of cyclic AMP- 14C (adenylate cyclase activity) of myometrium from pregnant rhesus monkeys (145–160 days) were measured. Adenylate cyclase activity was determined from the formation of cyclic AMP- 14C from ATP labeled by incubation with adenine-8- 14C. PGE 2 (2.8 μM) increased cyclic AMP- 14C levels both with and without caffeine (2.5 μmM). When 2.5 mM caffeine was present the effects of PGE 1 and PGE 2 (2.8 μM), like those of PGF 1α and PGF 2α, were similar; the PGE series, however, had a greater effect on cyclic AMP- 14C. Similar differences between the series E and F prostaglandins were observed in concentrations from 0.28 to 5.6 μM. Epinephrine also increased cyclic AMP- 14C levels of myometrium; the addition of propranolol (33 μM) decreased the effect of epinephrine but did not alter the effect of PGE 2. The basal level of cyclic AMP- 14C in the myometrium of pregnant rhesus monkeys was 2.5-fold higher than that of taenia coli from nonpregnant monkeys. The addition of caffeine to the medium increased cyclic AMP- 14C concentrations slightly in taenia coli and, on a percentage basis, the addition of PGE2 in the presence of 2.5 mM caffeine caused similar increases in cyclic AMP- 14C levels in taenia coli and in myometrium. Epinephrine (10 μM) also increased the cyclic AMP- 14C concentration of the taenia coli.