Testosterone supplementation may be protective against the development of Alzheimer's disease, according to US researchers.
Supplementation may be useful for both men and women as testosterone levels decline in elderly men and postmenopausal women, they say (Proceedings of the National Academy of Sciences 2000;97:1202).
Alzheimer's disease is characterised by plaques in the brain formed by the deposition of b-amyloid peptides. The researchers, from the Rockefeller University, New York, examined the effects of testosterone on secretion of b-amyloid in neuroblastoma cells and primary neurones from rats.
Testosterone was found to decrease the secretion of b-amyloid peptides by 30-45 per cent. It also increased secretion of harmless b-amyloid fragments by 50-75 per cent. Cholesterol and corticosterone (a glucocorticoid hormone) were ineffective at reducing b-amyloid secretion, leading the authors to conclude that the mechanism is specific to testosterone and oestrogen (which has previously been reported as possibly giving protection against the development of Alzheimer's disease).
However, they caution that the benefits of androgen supplementation have to be weighed against the potential deleterious effects, including the development of prostate cancer in men or endometrial cancer in women.