[Testosterone at physiological level inhibits PGF2alpha-induced increase in intracellular Ca2+ in cultured vascular smooth muscle cells].
OBJECTIVE
To explore the acute effects of testosterone at the physiological level on PGF2alpha-induced increase in intracellular Ca2+ in cultured vascular smooth muscle cells (VSMCs).


METHODS
VSMCs from the thoracic aorta of male Sprague-Dawley rats were cultured using the explant method. The subconfluent VSMCs were incubated with serum-free medium for 24 hours to obtain quiescent non-dividing cells and then treated with the indicated agents. For the measurement of [Ca2+]i, the VSMCs were loaded with fura-2. Changes of [Ca2+]i were determined ratiometrically with a Nikon TE-2000E system.


RESULTS
The resting level of [Ca2+]i was around 100 nmol/L in the VSMCs. Exposing cells to perfusate containing 10 micromol/L PGF2alpha triggered an immediate and transient peak in [Ca2+]i, which gradually decreased afterwards. Interference at the peak with the physiological concentration (40 nmol/L) of testosterone significantly decreased the peak-to-baseline time of [Ca2+]i, compared with ethanol vehicle (104.9 +/- 27.0 s vs 153.5 +/- 40.4 s, P < 0.01). Pretreatment with testosterone at 40 nmol/L for 2 minutes also reduced the peak-to-baseline time of [Ca2+]i significantly in comparison with the ethanol control (120.6 +/- 32.0 s vs 151.4 +/- 27.4 s, P < 0.01), but it had no significant effect on the peak level of PGF2alpha-induced intracellular Ca2+ (390.0 +/- 126.0 nmol/L vs 403.4 +/- 160.7 nmol/L, P > 0.05).


CONCLUSIONS
Testosterone at physiological concentration inhibits PGF2alpha-induced Ca2+ fluxes, probably via receptor-operated calcium channels by a non-genomic mechanism in VSMCs, which may be involved in the vasodilatory effect of testosterone.
Ma
Rui
R
Department of Cardiology, Nanjing General Hospital of Nanjing Military Region, Nanjing, Jiangsu 210002, China. rui_ma@126.com
Jiang
Shi-Sen
SS
Cheng
Xun-Min
XM
Gong
Jian-Bin
JB
Zhang
Qi-Gao
QG
Lin
Qi-Shui
QS
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D015237:Dinoprost / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013739:Testosterone / Q000378:metabolism* / Q000502:physiology
D013739:Testosterone; D015237:Dinoprost; D002118:Calcium