Dissociation of prolactin response to thyrotropin-releasing hormone and metoclopramide in chronic renal failure.

PRL secretion was evaluated in 14 males with chronic renal failure on long term hemodialysis. Twelve had basal hyperprolactinemia. Ten subjects were challenged with TRH in doses ranging from 200--1000 micrograms. None of them responded to 200 or 500 micrograms TRH, although 2 of 4 subjects tested did respond to 1000 micrograms TRH. In contrast, all 4 subjects challenged with metoclopramide did have PRL responses which were indistinguishable from those of the controls. These results indicate that there is a dissociation in responsiveness to metoclopramide and TRH in chronic renal failure.