Effects of testosterone on norepinephrine release in isolated rat heart / 华中科技大学学报（医学）（英德文版）

ABSTRACT

The effects of testosterone on norepinephrine release were investigated in the isolated rat hearts. Sprague-Dawley male rats (n=120) were randomized to testosterone and control groups. The rats in testosterone group were perfused with modified Krebs-Henseleit buffer containing different concentrations of testosterone (0.1, 1.0, 10.0, and 100.0 nmol/L, respectively). Myocardial ischemia was induced by globally stopping the perfusion flow. Exocytotic norepinephrine release was induced by electrical field stimulation at 5 V (effective voltage) and 6 Hz (pulse width of 2 ms) for 1 min. The overflow of norepinephrine was determined by high pressure liquid chromatography and electrochemical detection (HPLC-EC). Following acute ischemia, testosterone (1.0, 10.0 and 100.0 nmol/L) significantly reduced norepinephrine release (P0.05). Electrical stimulation of the ventricle evoked norepinepherine release, and this was diminished by the perfusion with testosterone at the concentrations of 1.0, 10.0 and 100.0 nmol/L (P<0.01). It is suggested that testosterone suppresses ischemia- and electrical stimulation-induced norepinepherine release in the isolated rat hearts.