A patient presents with amenorrhea and galactorrhea. Her PRL levels are elevated. She is presently not pregnant. In addition to evaluating her for a prolactinoma for the reason of her hyperprolactinemia, what other investigations can assess the cause of elevated PRL?

Causes of hyperprolactinemia are Pregnancy and lactation Drugs: dopamine antagonists, MAO inhibitors, cimetidine etc Pituitary tumours Hypothyroidism Renal and hepatic disorders TRH is a potent stimulator of PRL and may induce galactorrhea under conditions of primary hypothyroidism, which should be checked for by measuring TSH. PRL secretion is controlled by the inhibitory action of hypothalamic dopamine.