Prolactin
A protein hormone produced by the anterior pituitary that stimulates milk production in breastfeeding women. Prolactin levels can be affected by several peptide drug classes — somatostatin analogues may suppress prolactin, while some GnRH compounds can alter prolactin dynamics.
Technical Context
Prolactin (199 aa) is unique among anterior pituitary hormones in being tonically inhibited by hypothalamic dopamine (via D2 receptors on lactotrophs) rather than stimulated by a releasing hormone. TRH and VIP stimulate prolactin release. Somatostatin analogues can suppress prolactin secretion through SSTR5. Some GnRH compounds can transiently alter prolactin levels. Hyperprolactinaemia can be caused by prolactinomas (treated primarily with dopamine agonists, not peptide drugs) or as a side effect of drugs that reduce dopamine activity. Prolactin monitoring may be relevant during treatment with peptide drugs that affect hypothalamic-pituitary function.