Hypothyroidism may be associated with hyperprolactinaemia. If hypothyroidism results in increased TRH production, then TRH (which can act as a PRF), could lead to hyperprolactinaemia.
Oestrogens act directly at the pituitary level causing stimulation of lactotrophs and thus enhance prolactin secretion. Furthermore, oestrogens increase the mitotic activity of lactotrophs.
Injury to the chest wall can also lead to hyperprolactinaemia. The mechanism is unclear but probably results from abnormal stimulation of the reflex associated with the rise in prolactin that is seen normally in lactating women during suckling.
