Increased prolactin response to TRH in polycystic ovary syndrome with low basal prolactin values

An intravenous TRH loading test with 200 micrograms TRH was carried out in 9 hypoprolactinemic (serum prolactin less than 100 mIU/ml) and 6 normoprolactinemic PCO patients and 6 normal subjects. Basal and stimulated prolactin and TSH levels were measured. The latter were within normal values. Prolactin responses to TRH were exaggerated in PCO patients, irrespective of the basal prolactin values. According to literary data, these results indicate that increased prolactin response to TRH in PCO is independent of the basal prolactin values and suggest disturbed tuberoinfundibular dopaminergic function.