Testosterone cause of sex differences in the occurrence of Parkinson’s disease, new research suggests

Men are twice as likely as women to develop Parkinson's disease, a nervous system disorder characterized by tremors and difficulty moving. New research to be presented at Cardiovascular, Renal and Metabolic Diseases: Physiology and Gender suggests that the difference in risk may be due to the presence of the male sex hormone testosterone.

Parkinson's is due to the loss of dopamine neurons, cells in the region of the brain that controls movement. Oxidative stress, which is a chemical imbalance triggered by sources such as genetic mutations and exposure to environmental toxins, can harm and kill cells. Researchers at the University of North Texas Health Science Center observed in rats' dopamine neurons that testosterone exacerbated damage induced by oxidative stress, acting through a protein called cyclooxygenase 2 (COX2). Blocking the actions of COX2 blocked testosterone's effects. These data indicate that testosterone may enhance the damage and death in dopamine neurons induced by oxidative stress, explaining the sex differences in the occurrence of Parkinson's, the researchers wrote.

Lead investigator Shaletha Holmes will present "The Effects of Testosterone and Oxidative Stress on Neuroinflammatory Signaling in Dopamine Neurons" as part of the symposium "Immune System and Regenerative Medicine—Impact of Gender and Sex" on Wednesday, Nov. 18, at 9:15 AM in Wye Room and as part of the poster session "Neurocontrol" on Thursday, Nov. 19, from 1:30 to 2:30 PM in Rhode/Severn Room of the Crowne Plaza Annapolis Hotel.