To understand mechanisms controlling uterine tone during pregnancy, we studied effects of chronic treatment with the contractile agonist oxytocin on adenylyl cyclase activity in cultured late gestation (day 20) rat myometrial cells. At confluence, cells were exposed to growth medium with or without oxytocin (10]M) for 24 hours. Adenylyl cyclase activity was measured in washed membranes. When compared to controls, oxytocin-treated tissues showed reduced basal adenylyl cyclase activity (95±44 vs. 54+29 pmol cAMP/mg protein/10 min, respectively, means±SE, n=2). This reduction was also reflected in adenylyl cyclase activity induced by GTP (10"SM) [147±82 vs. 91±57], isoproterenol (10"M)[207±109 vs. 112±62], forskolin (10M) [1277±606 vs. 995±671], and aluminum fluoride [1044±616 vs. 804±523]. These findings suggest that chronic treatment with oxytocin inhibits adenylyl cyclase activity through a mechanism that is distal to the adrenergic receptor.
|Original language||English (US)|
|State||Published - 1996|
ASJC Scopus subject areas
- Molecular Biology