Human fetal hypothalamic GnRH neurosecretion: dopaminergic regulation in vitro

An in-vitro perifusion system was used to investigate GnRH release from fetal (21-23 weeks gestation) human hypothalami in response to dopamine (DA) and the DA receptor antagonist haloperidol. Administration of 1 mumol/l DA during five perifusions in which 1 mumol/l haloperidol was added to the medium failed to alter basal GnRH release. In contrast DA evoked a rapid and sustained 95.8 +/- 20.3% increase (P less than 0.01) in GnRH release during five matching perifusions with medium containing the alpha-adrenergic antagonist phentolamine. While exposure to 0.01 mumol/l DA failed to alter basal GnRH release during three perifusions, 0.1 mumol/l DA elicited a 145.7 +/- 65.2% increase (P less than 0.05) in GnRH release in three matching perifusions, indicating a dose-dependent effect. These studies demonstrate that DA can stimulate in-vitro release of GnRH from the mid-gestation fetal human hypothalamus by a DA receptor mediated mechanism.