Dopamine and prolactin axis

Dopamine and prolactin axis

Dopamine from the hypothalamus acts to inhibit prolactin secretion from the pituitary (see Fig. 11.3).

·        If the hypothalamic pituitary connection is disrupted, e.g. by stalk section or hypothalamic lesions then pituitary prolactin (PRL) secretion is uncontrolled.

·        PRL release is stimulated by drugs that block dopamine receptors (e.g. metoclopramide) or cause a reduction in hypothalamic dopamine (e.g. methyldopa). Stress, sleep and nipple stimulation increase PRL.

·        Oestrogens during pregnancy increase PRL secretion but also suppress milk production. As oestrogens fall postpartum, milk production accelerates.

·        Administration of dopamine or levodopa inhibits PRL release. Pituitary haemorrhage causing death of the lactotrophs results in failure of lactation (Sheehan’s syndrome).