SECRETION OF GROWTH-HORMONE AND THYROID-STIMULATING HORMONE IN PATIENTS WITH DEMENTIA

We studied the growth hormone (GH) response to GH-releasing hormone (G HRH) and the thyroid-stimulating hormone (TSH) response to thyrotropin -releasing hormone (TRH) in four groups of patients with dementia and examined whether GH and TSH secretion is altered in patients with Alzh eimer's disease. The four groups included those with Alzheimer's disea se (n = 28), parkinsonism with dementia (n = 10), progressive supranuc lear palsy with dementia (n = 10), and dementia of vascular origin (n = 28). The results showed no differences among the four groups in GH r esponse to GHRH (12.2 +/- 2, 10.7 +/- 2, 8.9 +/- 1.1, and 9.9 +/- 1.9 mu g/ml, respectively); there was no correlation between GH response t o GHRH and sex, stage of the disease, or cerebral atrophy. The proport ion of patients with exaggerated, normal, or lower GH response was sim ilar in the four groups. There were also no differences among the grou ps in terms of TSH response to TRH (9.2 +/- 0.9, 11.1 +/- 1, 11.1 +/- 1, and 10.3 +/- 1 mU/ml, respectively), nor was there a correlation be tween TSH response to TRH and sex, stage of the disease, cerebral atro phy, or GH response to GHRH. The proportion of those with exaggerated, normal, or lower TSH response was similar in the four groups. Cerebro spinal somatostatin levels were similar in Alzheimer's disease and vas cular dementia patients. These findings indicate that neither GH respo nse to GHRH nor TSH response to TRH provides a useful diagnostic adjun t in Alzheimer's disease patients.