Adrenergic stimulation of placental progesterone production

Cells from term human placentas were maintained in culture, and progesterone production was monitored over 24 h. The beta 1-adrenergic receptor agonist dobutamine (10(-5) M) and the beta 2-adrenergic receptor agonist terbutaline (10(-5) M) increased progesterone production by 36 +/- 19% and 49 +/- 8% (+/- SE), respectively, compared with that in controls (P less than 0.001). Propranolol (10(-5) M) completely blocked the stimulatory effects of both drugs. The cAMP analog 8-bromo-cAMP (0.5 mM) also significantly altered (increased) progesterone production compared with controls (P less than 0.001), but this effect was not blocked to a significant degree by propranolol. The alpha-adrenergic receptor agonist methoxamine (10(-4) - 10(-6) M) did not significantly alter placental progesterone production compared with controls, and the stimulatory effect of terbutaline on progesterone production was not significantly affected by blockade of the alpha-adrenergic receptor with phentolamine. These data indicate that placental progesterone production can be significantly modulated by stimulation of beta-adrenergic, but not by alpha-adrenergic, receptors. This response may be mediated by increased intracellular cAMP. These findings may be important in considering other metabolic functions of the placenta as well as the treatment of preterm labor.