The coupling between @entity842 (NO)- @entity6708 signaling pathway and @entity4090 (PRL) release in pituitary lactotrophs has been established previously. However, the messenger that mediates the action of this signaling pathway on hormone secretion and the secretory mechanism affected, @entity460 dependent or independent, have not been identified. In cultured pituitary cells, basal PRL release was controlled by spontaneous voltage-gated @entity460 influx and was further enhanced by depolarization of cells and stimulation with @entity1218 . Inhibition of constitutively expressed neuronal NO synthase decreased NO and @entity6708 levels and increased basal PRL release. The addition of a slowly releasable NO donor increased @entity6708 levels and inhibited basal PRL release in a time-dependent manner. Expression of @entity3623 also increased NO and @entity6708 levels and inhibited basal, depolarization-induced, and @entity1218 -induced PRL release, whereas inhibition of this enzyme decreased NO and @entity6708 production and recovered PRL release. None of these treatments affected spontaneous and stimulated voltage-gated @entity460 influx. At basal NO levels, the addition of permeable @entity6708 analogs did not inhibit PRL secretion. At elevated NO levels, inhibition of @entity6708 production and facilitation of its degradation did not reverse inhibited PRL secretion. These experiments indicate that NO inhibits @entity460 -dependent PRL secretion in a @entity6708 -independent manner and downstream of voltage-gated @entity460 influx.

XXXX inhibits @entity4090 secretion in pituitary cells downstream of voltage-gated @entity460 influx.

@entity6708 :: ('CHEBI:16356', 'Chemical') :: ['cGMP'] @entity4090 :: ('5617', 'Gene') :: ['prolactin'] @entity1218 :: ('CHEBI:35940', 'Chemical') :: ['TRH'] @entity842 :: ('MESH:D009569', 'Chemical') :: ['nitric oxide'] @entity460 :: ('MESH:D002118', 'Chemical') :: ['calcium'] @entity3623 :: ('4843', 'Gene') :: ['inducible NO synthase']
@entity842 :: (MESH:D009569,Chemical) :: ['Nitric oxide']
