Administration of testosterone is associated with a reduced susceptibility to myocardial ischemia.
This study investigated the impact of testosterone on myocardial ischemia-reperfusion injury and corresponding intracellular calcium ([Ca2+]i) metabolism. Nonorchiectomized mature male Wistar rats were randomly assigned to placebo, a single dose of testosterone undecanoate, or 5alpha-dihydrotestosterone. In a further series, orchiectomized rats were treated with placebo. After 2 wk of treatment, the hearts were removed and placed in a Langendorff setup. The isolated, buffer-perfused hearts were subjected to 30 min of no-flow ischemia and 30 min of reperfusion. Recovery of myocardial function was measured by analyzing pre- and postischemic left ventricular (LV) systolic/diastolic pressure and coronary perfusion pressure simultaneously, together with [Ca2+]i handling (aequorin luminescence). Calcium regulatory proteins were analyzed by Western blotting. LV weight/body weight ratio was increased after administration of testosterone vs. orchectomized rats. The recovery of contractile function was improved in testosterone-treated rats: at the end of the reperfusion, LV systolic pressure was higher and end-diastolic pressure was lower in testosterone-treated rats. End-ischemic [Ca2+]i and [Ca2+]i overload upon reperfusion was significantly lower in testosterone vs. orchiectomized rats, too. However, levels of calcium regulatory proteins remained unaffected. In conclusion, administration of testosterone significantly improves recovery from global ischemia. These beneficial effects are associated with an attenuation of reperfusion induced [Ca2+]i overload.
Callies
Frank
F
Department of Endocrinology, Medical University Hospital Wuerzburg, 97080 Wuerzburg, Germany. Callies_F@klinik.uni-wuerzburg.de.
Strömer
Hinrik
H
Schwinger
Robert H G
RH
Bölck
Birgit
B
Hu
Kai
K
Frantz
Stefan
S
Leupold
Andrea
A
Beer
Stephanie
S
Allolio
Bruno
B
Bonz
Andreas W
AW
D000331:Aequorin; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D004198:Disease Susceptibility; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects / Q000503:physiopathology; D007425:Intracellular Membranes / Q000378:metabolism; D008163:Luminescent Measurements; D008297:Male; D017202:Myocardial Ischemia / Q000503:physiopathology / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D019831:Sodium-Calcium Exchanger / Q000378:metabolism; D013739:Testosterone / Q000494:pharmacology*; D000099211:Phospholamban
D000331:Aequorin; D002118:Calcium; D002135:Calcium-Binding Proteins; D000252:Calcium-Transporting ATPases; D012739:Gonadal Steroid Hormones; D020033:Protein Isoforms; D019837:Ryanodine Receptor Calcium Release Channel; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D019831:Sodium-Calcium Exchanger; D013739:Testosterone; D000099211:Phospholamban