['Progesterone modulates dopamine (DA) release in corpus striatum. Our objective was to evaluate the effect of the i.c.v injection of the neurosteroid allopregnanolone (ALL), a progesterone metabolite on dopaminergic activity in the corpus striatum of rats under different gonadal hormonal conditions.', 'We have measured the concentrations of DOPA, DA and DOPAC (main metabolite of DA) in the corpus striatum in estrus and diestrus rats and in ovariectomized rats without hormonal replacement (OVX group) and primed with estrogen and progesterone (OVX(i) group). Additionally, we have used the aromatic acid decarboxylase inhibitor NSD in order to evaluate the function of tyrosine hydroxylase (TH), the rate-limiting enzyme of dopamine synthesis.', 'ALL significantly decreased the striatal concentrations of both DA and DOPAC in the estrus. On the other hand, ALL increased significantly the levels of DA in the OVX(i) group. The DOPA accumulation in OVX(i) after NSD treatment in the ALL-treated groups was greater than in the vehicle group. However, the estrus group did not modify the DOPA accumulation after NSD injection.'] Does allopregnanolone modulate striatal dopamingergic activity of rats under different gonadal hormones conditions?