TSH and prolactin responses to thyrotropin releasing hormone (TRH) and domperidone in patients with empty sella syndrome

The aim of this study was to investigate TSH and PRL response to TRH and domperidone, an antidopaminergic drug which does not cross the blood-brain barrier, in 16 patients with primary empty sella (PES) and either normal or elevated plasma PRL level and to compare it with the response observed in 8 patients with prolactinoma. In the patients with PES and hyperprolactinemia, the PRL response to TRH was significantly lower than in the controls and the patients with PES and normal PRL, which suggests there is impaired PRL synthesis and release in cases of PES with hyperprolactinemia. The TSH response to domperidone was significantly elevated in patients with PES and either normal or elevated PRL, as in patients with prolactinoma. The PRL response to domperidone was significantly reduced in patients with PES and hyperprolactinemia as in patients with prolactinoma. These results suggest that in PES as in prolactinoma the inhibiting dopaminergic tone is increased on the thyrotropic cells and reduced on the lactotropic cells in PES with elevated PRL and that some patients with PES might bear a microprolactinoma in the bottom of the sella which remained undetected by the CT scan.