Possible role of dopamine in diethylstilbestrol-elicited accumulation of cyclic AMP in incubated male rat hypothalamus.

Pimozide and haloperidol, the dopaminergic antagonists, have been shown to effectively block diethylstilbestrol (DES)-elicited [3H] adenosine 3', 5'-monophosphate (cAMP) accumulation in incubated hypothalami from immature male rats. Several noradrenergic antagonists (i.e. propranolol, MJ-1999 and phenoxybenzamine) failed to reduce [3H]cAMP levels significantly. Pimozide was found to be more specific than haloperidol as it did not effect norepinephrine (NE)-elicited formation of [3H]cAMP, while the latter blocker caused a 48% reduction of the stimulation by NE. Pimozide was also more potent than haloperidol in inhibiting DES-stimulated [3H]cAMP formation. It can be inferred from these data that as a result of DES-receptor interaction dopamine (DA) is released and in turn activates DA-sensitive adenylate cyclase in the hypothalamus.