Does activation of neurons in the infundibular nucleus in menopause prevent the occurrence of Alzheimer changes?
01 / 2002 - 01 / 2004
Menopause is characterized by dramatic loss of ovarian hormone secretion and a compensatory rise in plasma gonadotropins due to an activation of the luteinizing hormone-releasing hormone (LHRH) in the infundibular (= arcuate) nucleus of the hypothalamus. A surprising finding was that in the infundibular nucleus of 90% of the elderly control males, conspicuous Alzheimer changes (hyperphosphorylated tau and silver-staining of neurofibrillary changes) were observed, while only in 8-10% of menopausal women far fewer of these changes were found. This finding fits into our hypothesis that activated neurons are protected against Alzheimer changes ("use it or lose it"). The aim of our study is to investigate the mechanisms by which the neurons are activated and Alzheimer changes are prevented. Our hypothesis, on the basis of a pilot study, is that in menopausal women in the LHRH neurons and interneurons, oestrogen receptors are down-regulated, resulting in a strong metabolic activation of both neuron populations. In the metabolically hyperactive neurons we do not expect to fïnd hyperphosphorylated tau. Material of patients with abnormal hormone levels (males castrated for prostate cancer, males/females with hormone-producing tumors, males/females treated with sex hormones) allow us to distinguish cause and effect in the correlations observed.