What are the means of investigating hypothalamic-hypophyseal axis?

PRL and gonadotropin levels (increase of PRL in case of adenoma, if PRL increases endorphins increase and thus GnRH decrease), FSH and LH levels (increase in ovarian pathology) LHRH test (if low LH and FSH, evaluated mobilization of pituitary reserve not very imp) clomiphene citrate test (anti-estrogen for functional pathology trigger a cycle) Anatomic exploration (clinical and bio data)