EXPRESSION OF ESTROGEN-RECEPTOR-ALPHA AND ESTROGEN-RECEPTOR-BETA IN RAT-HEART - ROLE OF LOCAL ESTROGEN SYNTHESIS

The role of cardiac oestrogen receptor expression and local oestrogen synthesis in the pathogenesis of cardiovascular disease is poorly unde rstood. Therefore we studied the effects of the oestrogen precursors a ndrostendione and testosterone on the expression of cyp450 aromatase, oestrogen receptor a and beta, and inducible NO synthase (iNOS) in neo natal rat cardiac myocytes. Here, we show that cyp450 aromatase is exp ressed in cardiac myocytes and incubation of cardiac myocytes with oes trogen precursors leads to sexual dimorphic transactivation of an oest rogen-responsive reporter plasmid. Furthermore, incubation with oestro gen precursors stimulated expression of oestrogen receptor alpha and b eta, and iNOS in a gender-specific fashion. These data suggest that lo cal oestrogen biosynthesis of the heart is effective to activate oestr ogen receptor alpha and beta, and downstream target genes in a gender- based fashion and may therefore contribute to the beneficial effects o f oestrogen in the pathogenesis of cardiovascular disease.