Pituitary-Adrenal Axis And Thyroid Dysfunction In Alzheimer' Disease And Multi-infarct Dementia

Obejective:To identify pituitary-adrenal axis function change and thyroid dysfunction in Alzheimer'disease and Multi-infarct dementia.Methods:Serum levels of cortisol (F), adrenocorticotropic hormone (ACTH) and triiodothyronine (T,), thyroxine (T4), free T, (F3) ,free T4 (FT4), thyroid stimulating hormone (TSH) were determined by Automated Chemiluminescent immunoassay system or radioimmunoassay for -11 patients with Alzheimer'disease (AD), 23 patients with multi-infarct dementia (MID), 28 patients with multi-cerebral-infarction (MCI) and 23 healthy controls.A dexamethasone test (DST) was performed in 4 patients with AD,9 patients with MID, 7 patients with MCI.Results: l)Patients with AD,M1D showed significantly high serum cortisol than those with MCI and those healthy controls.No significant differences were found in serum ACTH among AD, MID, MCI and healthy controls. DST revealed 75%AD, 77.8%MID patients were nonsuppressors. 2)The serum T,, FT,, FT4 levels in patients with AD, MID and MCI were lower than that in the control group. No significant differences were found in serum T, ,TSH between three patients groups and the healthy control. 3)Among three patients groups: three were no significant differences in serum T1,T4,TSH , FT4 and ACTH levels; but serum FT, level was lower in patients with MID as compared with MCI, the serum cortisol level was higher in patients with AD and MID than those with MCI and healthy control.Conclusions: These results suggest that lower thyroid hormone might play a role in the pathophysiologic process of AD ; the function state and serum hormone levels of thyroid might be one of factors in the development of MID; serum FT3 levelcould be used as a marker of congitive decline of ischemic cerebral vascular disease.There were pituitary-adrenal axis dysfunction in patients with AD and MID, but the causation of the abnormal pituitary-adrenal axis and AD or MID is not definite.