Endocrine responses to growth hormone releasing hormone and corticotropin releasing hormone in early-onset Alzheimer's disease.
In a study of the hypothalamic-pituitary-somatotropic (HPS) and the hypothalamic-pituitary-adrenal (HPA) systems in early-onset Alzheimer's disease (AD), 10 drug-naive patients and matched controls were given 50 micrograms growth hormone releasing hormone (GHRH) at 9 a.m. and 100 micrograms corticotropin releasing hormone (CRH) at 6 p.m. as an i.v. bolus dose. Compared with controls, patients with AD showed attenuated GHRH-induced growth hormone (GH) responses and decreased adrenocorticotropic hormone (ACTH) but normal cortisol secretion following CRH. GH responses to GHRH were negatively correlated with the plasma insulin-like growth factor (IGF-I) concentrations and the severity of dementia. A positive correlation was found between GHRH-evoked GH release and ACTH responses to CRH. The results suggest a pathological process at the level of the pituitary or the hypothalamus, possibly involving a cholinergic, monoaminergic, or peptidergic imbalance in AD, and support the view that altered HPS and HPA secretory dynamics in AD are related to the underlying brain dysfunction.
Lesch
K P
KP
Department of Psychiatry, University of Würzburg, FRG.
Ihl
R
R
Frölich
L
L
Rupprecht
R
R
Müller
U
U
Schulte
H M
HM
Maurer
K
K
D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000368:Aged; D000544:Alzheimer Disease / Q000097:blood* / Q000175:diagnosis; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D011863:Radioimmunoassay
D007334:Insulin-Like Growth Factor I; D000324:Adrenocorticotropic Hormone; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D006854:Hydrocortisone