RAPID COMMUNICATION
Sex Differences in Connexin-43 Expression in
Left Ventricles of Aging Rats
N. TRIBULOVÁ1, E. DUPONT2,
T. SOUKUP3, L. OKRUHLICOVÁ1,
N.J. SEVERS2
1Institute for Heart Research, Slovak Academy of
Sciences, Bratislava, Slovak Republic, 2Imperial
College, Royal Brompton Hospital, London, UK and 3Institute
of Physiology, Czech Academy of Sciences, Prague, Czech Republic
Received August 19, 2005
Accepted September 5, 2005
Summary
Cardiac gap junctions have been implicated in maintaining
intercellular electrical and metabolic couplings. The
abnormalities in connexin-43 (Cx43) lead to conduction defects
and contractile dysfunction. We have evaluated the expression
and phoshorylation status of Cx43 in the left ventricular
myocardium of male and female 16-month-old rats submitted to
14-week L-thyroxine (T4) treatment. Western blot analysis
revealed the presence of fully or intermediately phosphorylated
and unphosphorylated forms of Cx43. We have found no significant
differences in Cx43 expression and phosphorylation between
T4-treated and control untreated animals. However, expression of
Cx43 was significantly higher in female compared to male rats.
We conclude that T4 administration has no effect on Cx43
expression, but there are sex-dependent differences in Cx43
expression in the left ventricles between aging male and female
rats.
Key words
Connexin-43 • Rat cardiomyocytes • Steroid and thyroid hormones
• Male and female specificity
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