ABNORMAL TSH, PRL AND GH RESPONSE TO TSH RELEASING FACTOR IN CHRONIC RENAL-FAILURE

TSH, PRL and GH [thyrotropin, prolactin and growth hormone, respectively] response to TSH releasing factor and basal T4 and T3 [thyroxine and triiodothyronine, respectively] were evaluated in a group of patients with chronic renal failure undergoing chronic hemodialysis. Serum T4 and T3 were lower than normal. Basal TSH was normal as compared to control, but did not rise after TRF [TSH-releasing factor] stimulation. Larger dosages of TRF did not correct this abnormal response. Basal PRL was higher than control and remained at the same level during the test. GH was stimulated by the TRF with a peak occurring 20 min after injection. This abnormal secretion was not blunted by T3 administraion. TRF half-life measured in 3 patients was 4 min. There is probably an abnormal response to TRF in chronic renal failure which does not seem to be due to an altered sensitivity to, or metabolism of TRF. There is probably an abnormal TSH secretion which may be responsible for the low T4 and T3 measured in these patients.