Some examples include women with a persistent mildly elevated prolactin; in patients taking long-term dopamine antagonists with the expected elevated prolactin where the question of a possible underlying pituitary adenoma as the cause has been raised and the dopamine antagonist cannot be withdrawn (for example antipsychotic medication); or in men with low testosterone where a pituitary adenoma causing secondary hypogonadism as the cause has been suggested. This evidence concerns the gene PRL and hypogonadotropic hypogonadism.