We selected 5 patients, between 18 and 31 years of age, presenting menstrual irregularities and thyroidal goiter with no apparent functional change (normal, T4 and T3 tests). These patients underwent further examinations: TSH (basal and after TRH stimulation), HPRL (basal-circadian rhythm and after TRH stimulation), FSH and LH (basal and after Gn-RH stimulation), thyroidal scintiscan, search for antithyroid antibodies. Basal and post-stimulation TSH was fundamental in 2 cases of subclinical hypothyroidism. The positive antibody search confirmed the antoimmune origin. In the same patients, the HPRL circadian rhythm and TRH test highlighted a secondary hyperprolactinemia which would not have been revealed by a single basal sample.