Steroid hormones exert their action by

Tracy Marsden holds both a BSc and a BSc in Pharmacy. She received a Diploma in Homeopathic Pharmacy in 1996, and was subsequently awarded a Fellowship in the British Institute of Homeopathy. She was a community pharmacist for 15 years. Tracy is a Past-President of the Alberta College of Pharmacists and has given presentations and written articles on all areas of natural health for public and professional audiences. She is co-author of the Canadian bestseller, You've Hit Menopause: Now What?, and is currently Vice-President and part-owner of Rocky Mountain Analytical, Canada's largest laboratory specializing in preventive testing ().

Sex steroids exert pleiotropic effects in the nervous system, preserving neural function and promoting neuronal survival. Therefore, the age-related decrease in sex steroids may have a negative impact on neural function. Progesterone, testosterone and estradiol prevent neuronal loss in the central nervous system in different experimental animal models of neurodegeneration. Furthermore, progesterone and its reduced derivatives dihydroprogesterone and tetrahydroprogesterone reduce aging-associated morphological abnormalities of myelin and aging-associated myelin fiber loss in rat peripheral nerves. However, the results from hormone replacement studies in humans are thus far inconclusive. A possible alternative to hormonal replacement therapy is to increase local steroidogenesis by neural tissues, which express enzymes for steroid synthesis and metabolism. Proteins involved in the intramitochondrial trafficking of cholesterol, the first step in steroidogenesis, such as the peripheral-type benzodiazepine receptor and the steroidogenic acute regulatory protein, are up-regulated in the nervous system after injury. Furthermore, steroidogenic acute regulatory protein expression is increased in the brain of 24-month-old rats compared with young adult rats. This suggests that brain steroidogenesis may be modified in adaptation to neurodegenerative conditions and to the brain aging process. Furthermore, recent studies have shown that local formation of estradiol in the brain, by the enzyme aromatase, is neuroprotective. Therefore, steroidogenic acute regulatory protein, peripheral-type benzodiazepine receptor and aromatase are attractive pharmacological targets to promote neuroprotection in the aged brain.

Steroid hormones exert their action by

steroid hormones exert their action by


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