<prompt> For galactorrhea and amenorrhea syndromes, what is the investigation in addition to serum prolactin?LHTSHUrinary Keto-steroidsHCG  <response>: In patients with Iodine deficiency Low T4T3 results in TSH by Feedback mechanism to TSH the TRH is also elevated Now this TRH will increase both TSH and Prolactin production. Therefore Hyperprolactinemia resulting in Galactorrhea can also be seen in Patients with thyroid malfunction. 