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Santti R, Mäkelä S, Strauss L, Korkman J, Kostian ML. Toxicol
Ind Health 1998 Jan-Apr 14:1-2 223-37
Abstract
Exposure to diethylstilbestrol (DES) induces persistent
structural and functional alterations in the developing reproductive
tract of males. It is possible that xenoestrogens other than DES
alter sexual differentiation in males and account for the increasing
incidence of developmental disorders of the reproductive tract in
men and wild animals. Phytoestrogens (coumestans, isoflavonoids,
flavonoids, and lignans) present in numerous edible plants are quantitatively
the most important environmental estrogens when their hormonal potency
is assessed in vitro. They exert their estrogenic activity by interacting
with estrogen receptors (ERs) in vitro. They may also act as antiestrogens
by competing for the binding sites of estrogen receptors or the
active site of the estrogen biosynthesizing and metabolizing enzymes,
such as aromatase and estrogen-specific 17 beta-hydroxysteroid oxidoreductase
(type 1). In theory, phytoestrogens and structurally related compounds
could harm the reproductive health of males also by acting as antiestrogens.
There are very little data on effects of phytoestrogens in males.
Estrogenic effects in wildlife have been described but the evidence
for the role of phytoestrogens is indirect and seen under conditions
of excessive exposure. In doses comparable to the daily intake from
soybased feed, isoflavonoids such as genistein were estrogen agonists
in the prostate of adult laboratory rodents. When given neonatally,
no persistent effects were observed. In contrast, the central nervous
system (CNS)-gonadal axis and the male sexual behavior of the rat
appear to be sensitive to phytoestrogens during development. The
changes were similar but not identical to those seen after neonatal
treatment with DES, but higher doses of phytoestrogens were needed.
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