Hello and welcome to the Zero to Finals podcast.

My name is Tom and in this episode I'm going to be talking to you about prolactin.

And you can find written notes on this topic at zero to finals.com slash prolactin

or in the Zero to Fin endocrine system book,

which is coming soon. And you can find flashcards and questions to train your knowledge

and help you remember the information for longer at members.0 tofinals.com. So let's get straight into it.

Prolactin is a hormone produced by the anterior pituitary gland.

Its primary functions are to stimulate glandular breast tissue development

and breast milk production.

Let's start with the control of prolactin.

Factors that stimulate prolactin production by the anterior pituitary gland

include nipple stimulation, for example, suckling by a baby,

thyrotropin releasing hormone, or TRH from the hypothalamus,

elevated estrogen levels, for example during pregnancy, stress, and sleep.

Progesterone inhibits the effects of prolactin on the breast tissue.

This prevents breast milk production during pregnancy when there's high levels of progesterone.

After birth, progesterone levels fall rapidly, allowing prolactin to carry out its effects.

Dopamine, which is an important neurotransmitter, inhibits the secretion of prolactin.

Here's some clinical relevance.

Dopamine antagonists, for example antipsychotic medications, work to inhibit

dopamine receptors. Inhibiting dopamine allows prolactin levels to rise. Remember, dopamine inhibits

the secretion of prolactin. A rise in prolactin causes gynecomastia, which is glandular breast

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