title: Testosterone deprivation accelerates cardiac dysfunction in obese male rats.
abstract: Low testosterone level is associated with increased risks of cardiovascular diseases. As obese-insulin-resistant condition could impair cardiac function and that the incidence of obesity is increased in aging men, a condition of testosterone deprivation could aggravate the cardiac dysfunction in obese-insulin-resistant subjects. However, the mechanism underlying this adverse effect is unclear. This study investigated the effects of obesity on metabolic parameters, heart rate variability (HRV), left ventricular (LV) function, and cardiac mitochondrial function in testosterone-deprived rats. Orchiectomized or sham-operated male Wistar rats (n=36per group) were randomly divided into groups and were given either a normal diet (ND, 19.77% of energy fat) or a high-fat diet (HFD, 57.60% of energy fat) for 12weeks. Metabolic parameters, HRV, LV function, and cardiac mitochondrial function were determined at 4, 8, and 12weeks after starting each feeding program. We found that insulin resistance was observed after 8weeks of the consumption of a HFD in both sham (HFS) and orchiectomized (HFO) rats. Neither the ND sham (NDS) group nor ND orchiectomized (NDO) rats developed insulin resistance. The development of depressed HRV, LV contractile dysfunction, and increased cardiac mitochondrial reactive oxygen species production was observed earlier in orchiectomized (NDO and HFO) rats at week 4, whereas HFS rats exhibited these impairments later at week 8. These findings suggest that testosterone deprivation accelerates the impairment of cardiac autonomic regulation and LV function via increased oxidative stress and impaired cardiac mitochondrial function in obese-orchiectomized male rats.
authors.affiliation: Cardiac Electrophysiology Research and Training CenterFaculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Cardiac Electrophysiology UnitDepartment of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Center of Excellence in Cardiac Electrophysiology ResearchChiang Mai University, Chiang Mai, Thailand.
authors.forename: Wanpitak
authors.initials: W
authors.lastname: Pongkan
authors.affiliation: Cardiac Electrophysiology Research and Training CenterFaculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Cardiac Electrophysiology UnitDepartment of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Center of Excellence in Cardiac Electrophysiology ResearchChiang Mai University, Chiang Mai, Thailand.
authors.forename: Hiranya
authors.initials: H
authors.lastname: Pintana
authors.affiliation: Cardiac Electrophysiology Research and Training CenterFaculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Cardiac Electrophysiology UnitDepartment of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Center of Excellence in Cardiac Electrophysiology ResearchChiang Mai University, Chiang Mai, Thailand.
authors.forename: Sivaporn
authors.initials: S
authors.lastname: Sivasinprasasn
authors.affiliation: Cardiac Electrophysiology Research and Training CenterFaculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Cardiac Electrophysiology UnitDepartment of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Center of Excellence in Cardiac Electrophysiology ResearchChiang Mai University, Chiang Mai, Thailand.
authors.forename: Thidarat
authors.initials: T
authors.lastname: Jaiwongkam
authors.affiliation: Cardiac Electrophysiology Research and Training CenterFaculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Cardiac Electrophysiology UnitDepartment of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Department of Oral Biology and Diagnostic ScienceFaculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Siriporn C
authors.initials: SC
authors.lastname: Chattipakorn
authors.affiliation: Cardiac Electrophysiology Research and Training CenterFaculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Cardiac Electrophysiology UnitDepartment of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand Center of Excellence in Cardiac Electrophysiology ResearchChiang Mai University, Chiang Mai, Thailand nchattip@gmail.com.
authors.forename: Nipon
authors.initials: N
authors.lastname: Chattipakorn
mesh_terms: D000818:Animals; D002318:Cardiovascular Diseases / Q000209:etiology* / Q000503:physiopathology; D059305:Diet, High-Fat / Q000009:adverse effects; D006339:Heart Rate / Q000502:physiology; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008315:Malondialdehyde / Q000097:blood / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial; D008929:Mitochondria, Heart / Q000502:physiology; D008933:Mitochondrial Swelling; D009765:Obesity / Q000150:complications* / Q000503:physiopathology; D009919:Orchiectomy; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000172:deficiency* / Q000502:physiology; D018487:Ventricular Dysfunction, Left / Q000209:etiology / Q000503:physiopathology
chemical_list: D013739:Testosterone; D008315:Malondialdehyde
keywords: cardiac function; cardiac mitochondrial function; obese-insulin resistance; testosterone deprivation