A list of the major causes of hyperprolactinaemia is given below. The most common cause of hyperprolactinaemia are small benign microadenomas of the pituitary (that release excess levels of prolactin). Most of the other causes of hyperprolactinaemia act either directly or indirectly on the hypothalamic dopaminergic system. In order to understand the other causes it is important to remember that prolactin release from the adenohypophysis is under predominantly negative control from dopamine release from the hypothalamus. Therefore, anything that interferes with this dopamine release will result in increased release of prolactin from the pituitary. Thyrotrophin releasing hormone (TRH) can also act to increase prolactin release.
The major causes of Hyperprolactinaemia: