Effects of the isoflavone genistein on cardiac gene expression in ovariectomized mice
Phytotherapie Kongress, Berlin Februar 2008
Nguyen BT, Wuttke W, Jarry H (Dept. für Endokrinologie Universitaetsmedizin Goettingen, Germany)
Overview
and
methods:
Instead
of
synthetic
hormones,
phytoestrogens
like
the
isoflavone
genistein
(Gen)
are
increasingly
used
to
treat
diseases
related
to
low
endogenous
estradiol
(E2)
production.
Despite
the
presence
of
both
known
types
of
estrogen
receptors
(ER)
in
the
heart,
little
is
known
about
putative
actions
of
phytoestrogens
in
the
heart.
To
assess
effects
of
a
long
term
treatment
with
Gen
on
cardiac
expression
of
ERs
and
estrogen-regulated
genes,
ovariectomized
mice
were
fed
for
3
months
with
a
Gen
or
E2-containing
diet.
Gene
expression
in
the
heart
was
determined
by
real
time
PCR.
Serum
concentrations
of
E2
and
Gen
were
measured
by
radioimmunoassay
or
HPLC,
respectively.
Results: Long term application of E2 or Gen via pelleted food resulted in physiological serum levels of both compounds. Surprisingly, neither E2 nor Gen affected expression of ERa or b in the heart. Expression of the structural protein actin alpha 2 was up-regulated by E2, but down-regulated by Gen. Only Gen affected cardiac expression of the arylhydrocarbon receptor. All observed changes were significant at the level of p < 0.05 as tested with ANOVA followed by Dunnett’s test.
Conclusions: The present data are the first evidence of effects of phytoestrogens in the heart. Though phytoestrogens like Gen bind to ERs, their effects on cardiac gene expression are distinct from those of E2.
