TRH stimulation test in healthy elderly: paradoxical response of growth hormone is abnormal in normal aging

The purpose of this study was to measure TSH (thyrotropin), PRL (prolactin) and GH (growth hormone) response to a TRH (thyrotropin releasing hormone) stimulation test in 37 healthy elderly male subjects and determine if these responses correlate with the incidence of mental decline; and also, to determine if these responses occur more frequently in the elderly than in the general population. A hyperresponse of TSH was documented in 7 of our 37 elderly male subjects, a delayed response of TSH in 4, a low response of PRL in 29 and a significant paradoxical response of GH in 2. Those subjects with a significant paradoxical response of GH were 82 and 83 years of age and their HDS was 20.0 and 25.5, respectively. We did not find a causal relationship between mental decline and the paradoxical response of GH, but our data suggests that the paradoxical response of GH is not normal in elderly older than 80 years old.