Dopamine inhibits prolactin secretion through its interactions with dopamine receptors in the pituitary gland.
The hypothalamus, located at the base of the brain, produces dopamine, which then travels to the anterior pituitary gland. In the anterior pituitary, dopamine acts on specialized cells called lactotrophs, which are responsible for prolactin production.
When dopamine binds to its specific receptors on lactotrophs, it triggers a cascade of intracellular events that ultimately inhibit the secretion of prolactin. This inhibitory effect of dopamine on prolactin is mediated primarily through the activation of D2 receptors, which are abundantly expressed on lactotrophs.
Activation of D2 receptors by dopamine leads to the inhibition of intracellular signaling pathways that are necessary for prolactin synthesis and release. Dopamine reduces the synthesis of prolactin by decreasing the transcription and translation of prolactin mRNA, as well as inhibiting the post-translational processing and packaging of prolactin into secretory granules.
In addition to directly inhibiting prolactin synthesis, dopamine also decreases the responsiveness of lactotrophs to other stimuli that promote prolactin secretion. For example, it inhibits the actions of other hormones such as thyrotropin-releasing hormone (TRH) and vasoactive intestinal peptide (VIP), which typically stimulate prolactin release.
Overall, the inhibitory effect of dopamine on prolactin secretion is a crucial regulatory mechanism that helps maintain appropriate prolactin levels in the body.
how dopamine inhibits prolactin secretion
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