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Effects of Soy Phytoestrogens and Genistein on Male Health
Cytotoxic
potential of the phytochemical genistein isoflavone
(4',5',7-trihydroxyisoflavone) and certain environmental chemical
compounds on testicular cells.
Kumi-Diaka
J, Nguyen V, Butler A
Biol
Cell 1999 Vol 91 515-523
Abstract
The effects
of genistein (Gn), sodium azide (naz), and dexamethasone (dxm) on
testicular cells TM3, TM4 and GC-1 spg were studied in vitro. First, a
series of experiments were performed to assess the response of the
cells to the exposure of Gn, naz, dxm, a combination of Gn with naz and
Gn with dxm. Trypan blue exclusion assay was used to determine the
percentage of viability, and LDH-cytotoxicity test was used to assess
the degree of treatment-induced cytotoxicity on each cell type. A
second series of experiments were performed to study cytomorphology and
determine the type and percentage of treatment-induced cell death
(apoptosis and necrosis) on each cell line, using fluorescent dye
technique to detect apoptotic and necrotic cells, and tunnel assay to
confirm apoptosis. The results from the data obtained demonstrated: i)
that incubation of testis cells with each of the agents (Gn, dxm, naz)
alone and in two combinations (Gn-dxm, and Gn-naz) induced significant
testicular cell death; ii) that both genistein and dexamethasone mostly
and significantly induced apoptotic cell death while sodium azide
induced necrotic cell death; iii) that addition of dexamethasone to
genistein demonstrated synergism in apoptosis on testis cells; and iv)
that combination of naz with Gn demonstrated synergism in necrosis on
testis cells even though Gn alone did not induce significant necrosis.
It is concluded that the synergistic actions of genistein and dxm, and
of genistein + sodium azide in induction of apoptosis and/or necrosis
may be of clinical and pathophysiological research interest considering
the chemopreventive and chemotherapeutic potential of genistein; and
the clinico-pharmacological application of dexamethasone and sodium
azide.
Dietary
soy-phytoestrogens decrease testosterone levels and prostate weight
without altering LH, prostate 5alpha-reductase or testicular
steroidogenic acute regulatory peptide levels in adult male
Sprague-Dawley rats.
Weber KS,
Setchell KD, Stocco DM, Lephart ED
J
Endocrinol 2001 Vol 170:591-9
Abstract
Nutritional
factors, especially phytoestrogens, have been extensively studied for
their potential beneficial effects against hormone-dependent and
age-related diseases. The present study describes the short-term
effects of dietary phytoestrogens on regulatory behaviors (food/water
intake, locomotor activity and body weight), prostate weight, prostate
5alpha-reductase enzyme activity, reproductive hormone levels, and
testicular steroidogenic acute regulatory peptide (StAR) levels in
adult Sprague-Dawley rats. Animals were fed either a phytoestrogen-rich
diet containing approximately 600 microg/g isoflavones (as determined
by HPLC) or a phytoestrogen-free diet. After 5 weeks of consuming these
diets, plasma phytoestrogen levels were 35 times higher in animals fed
the phytoestrogen-rich vs phytoestrogen-free diets. Body and prostate
weights were significantly decreased in animals fed the
phytoestrogen-rich diet vs the phytoestrogen-free fed animals; however,
no significant change in prostate 5alpha-reductase enzyme activity was
observed between the treatment groups. Locomotor activity levels were
higher in the phytoestrogen-rich vs the phytoestrogen-free animals
during the course of the treatment interval. Plasma testosterone and
androstenedione levels were significantly lower in the animals fed the
phytoestrogen-rich diet compared with animals fed the
phytoestrogen-free diet. However, there were no significant differences
in plasma LH or estradiol levels between the diet groups. Testicular
StAR levels were not significantly different between the
phytoestrogen-rich vs the phytoestrogen-free fed animals. These results
indicated that consumption of dietary phytoestrogens resulting in very
high plasma isoflavone levels over a relatively short period can
significantly alter body and prostate weight and plasma androgen
hormone levels without affecting gonadotropin or testicular StAR
levels. The findings of this study identify the biological actions of
phytoestrogens on male reproductive endocrinology and provide insights
into the protective effects these estrogen mimics exert in male
reproductive disorders such as benign prostatic hyperplasia and
prostate cancer.
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