Testosterone Modulates Cardiomyocyte Ca2 Handling and Contractile Function
CL Curl, LMD Delbridge, BJ Canny, IR Wendt
PHYSIOLOGICAL RESEARCH | ACAD SCIENCES CZECH REPUBLIC, INST PHYSIOLOGY | Published : 2009
The extent to which sex differences in cardiac function may be attributed to the direct myocardial influence of testosterone is unclear. In this study the effects of gonadal testosterone withdrawal (GDX) and replacement (GDX+T) in rats, on cardiomyocyte shortening and intracellular Ca(2+) handling was investigated (0.5 Hz, 25 oC). At all extracellular [Ca(2+)] tested (0.5-2.0 mM), the Ca(2+) transient amplitude was significantly reduced (by approximately 50 %) in myocytes of GDX rats two weeks post-gonadectomy. The time course of Ca(2+) transient decay was significantly prolonged in GDX myocytes (tau, 455+/-80 ms) compared with intact (279+/-23 ms) and GDX+T (277+/-19 ms). Maximum shortening..View full abstract
The funding support of the National Health and Medical Research Council of Australia, the Australian Research Council, and the National Heart Foundation of Australia is acknowledged.