Failure of bromocriptine, dopamine, and thyrotropin-releasing hormone to affect prolactin secretion by human decidual tissue in vitro.

To determine whether the secretion of PRL by human decidual tissue in vitro is influenced by factors which inhibit or stimulate pituitary PRL secretion, explants of decidual tissue were incubated in media containing bromocriptine, dopamine, or TRH at concentrations known to affect pituitary PRL secretion in vitro. The quantities of PRL secreted by the explants exposed to these factors were compared with amounts secreted by explants incubated in control medium. Bromocriptine in concentrations ranging from 1.5 x 10(-10) to 1.5 x 10(-7) M did not inhibit PRL secretion over a 3-day period and dopamine in concentrations ranging from 5 x 10(-5)-10(-9) M did not inhibit PRL secretion over a 4-h period. TRH in concentrations ranging from 10(-9)-10(-3) M did not stimulate PRL secretion. These results suggest that the mechanism of PRL secretion by decidual tissue in vitro is different, at least in part, from the mechanism of pituitary PRL secretion.