Phytoestrogens: potential endocrine disruptors in males
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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