In vitro effect of ritodrinum on cAMP concentration in human placentas of different gestational age.

Beta-sympathomimetic drugs are clinically widely used in the management of threatened premature labour. The existence of beta-adrenergic receptors has been demonstrated in the human placenta and, as the stimulation of beta-adrenoreceptors is known to be mediated by cAMP, the purpose of this study was to compare the effect of Ritodrinum on cAMP concentration in placentas of different gestational age. The in vitro treatment with Ritodrinum induced a five fold increase in cAMP concentration in 6-8 week old placenta, three fold increase in midgestation, but was without effect in term placenta. This result suggest that beta-mimetics in pharmacological concentrations could modulate trophoblast cell activity through the cAMP-dependent system during the first half of gestation.