An association of elevated serum gonadotropin concentrations and Alzheimer disease?

Alzheimer disease affects almost 4 million Americans and costs $65 billion annually. The disease is more common in women than in men, and studies suggest that oestrogen may have a protective effect. Oestrogen replacement lowers circulating concentrations of gonadotropins. When gonadotropins are added to rat granulosa cells in culture, the number of low density lipoprotein (LDL) receptors and the rate of uptake of low density lipoprotein increases. Many proteins found in Alzheimer disease plaques are ligands for low density lipoprotein receptors (LDLR) on central nervous system (CNS) neurones. This study evaluated whether gonadotropins may be associated with Alzheimer disease. Circulating concentrations of follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels in 40 male residents of long-term care facilities with the primary diagnosis of dementia were compared to 29 age-matched controls. Serum concentrations of FSH and LH were significantly higher in dementia patients. We speculate they may play an aetiologic role in the deposition of abnormal proteins, particularly those associated with low density lipoprotein receptors, in CNS neurones.