Effects of soy on rats, mice, birds and cattle
Rats & Mice:
Letter: The chance discovery of oestrogenic activity in laboratory
rat cake.
Drane H, Patterson DS, Roberts BA, Saba N
Food Cosmet Toxicol 1975 Aug 13:4 491-2
Oestrogenic activity of soya-bean products.
Drane HM, Patterson DS, Roberts BA, Saba N
Food Cosmet Toxicol 1980 Aug 18:4 425-7
Dietary genistein exerts estrogenic effects upon the uterus,
mammary gland and the hypothalamic/pituitary axis in rats.
Santell RC, Chang YC, Nair MG, Helferich WG
J Nutr 1997 Feb 127:2 263-9
Abstract
These studies were undertaken to assess the estrogenic and
antiestrogenic effects of dietary genistein.
To determine estrogenic effects, genistein was mixed into a modified
AIN-76 or AIN-93G semipurified diet at 0 (negative control), 150, 375
or 750 microg/g and 17, beta-estradiol at 1.0 microg/g and fed to
ovariectomized 70-d-old Sprague-Dawley rats.
Estrogenic potency was determined by analyzing uterine weight,
mammary gland development, plasma prolactin and expression of uterine
c-fos.
Dietary genistein (375 and 750 microg/g) increased uterine wet and
dry weights (P < 0.05). Mammary gland regression following
ovariectomy was significantly inhibited by dietary genistein at 750
microg/g (P < 0.05). Plasma prolactin was significantly greater in
ovariectomized rats fed genistein (750 microg/g) compared with
comparable rats not receiving genistein. The relative binding affinity
of genistein to the estrogen receptor (ER) was 0.01 that of estradiol.
Genistein (750 microg/g) induced the uterine expression of c-fos.
To evaluate potential antiestrogenic effects, genistein and
estradiol were mixed into the modified AIN diets at the doses noted
above and fed to ovariectomized rats.
Dietary genistein (375 or 750 microg/g) did not inhibit the effects
of estradiol on uterine weight, mammary gland development or plasma
prolactin. Serum concentration of total genistein (conjugated plus
free) in rats fed 750 microg/g was 2.2 micromol/L and free genistein
was 0.4 micromol/L.
Administration of dietary genistein at 750 microg/g can exert
estrogenic effects in the uterus, mammary gland and
hypothalamic/pituitary axis. Dietary genistein (750 microg/g) did not
antagonize the action of estradiol in estradiol supplemented
ovariectomized rats or in intact rats.
Birds:
Phytoestrogens: adverse effects on reproduction in California
quail
Leopold AS, Erwin M, Oh J, Browning B
Science 1976 Jan 9 191:4222 98-100
Abstract
Phytoestrogens, largely formononetin and genistein, are produced in
the leaves of stunted desert annuals in a dry year. When ingested by
California quail, these compounds apparently inhibit reproduction and
prevent the production of young that will not have adequate food. In a
wet year, forbs grow vigorously and phytoestrogenic substances are
largely absent. Quail then breed prolifically and the abundant seed
crop carries the enlarged population through the winter.
Effects of dietary and parenteral estrogens on bobwhite
reproduction.
Lien RJ, Cain JR, Beasom SL
Poult Sci 1987 Jan 66:1 154-61
Abstract
Bobwhites were fed one of several doses (.01 to 1,000
micrograms/day) of estriol (E3), beta-estradiol-3-benzoate (E2B),
diethylstilbestrol (DES), or biochanin-A (BA) during two 10-week
trials.
The initial 2 weeks of each trial were short day length (10L:14D)
followed by 8 weeks of long day length (16L:8D). In addition, female
bobwhites were given daily injections containing dosages (.01 to 10
micrograms/day) of E2B, E3, and DES while housed on the same light
regimen.
Reproductive performance as assessed by onset of lay, egg
production, and egg fertility was depressed in a dose-dependent manner
and was inhibited by dietary dosages of 1,000 micrograms/day of E3,
DES, and E2B.
No consistent effects on reproductive performance were observed in
bobwhites fed up to 1,000 micrograms/day of the phytoestrogen BA.
Injected estrogens appeared approximately 100 times more potent than
dietary estrogens.
It was concluded that both dietary and parenteral estrogen can
inhibit reproduction, but in order for phytoestrogen (BA) in natural
feedstuffs to impair reproduction in bobwhites it would have to be
consumed in excess of 1 mg/day.
Cattle:
Investigations in central Hessia on the occurrence of estrogenic
activity content of cattle feed]
Khodabandehlou H, Hoffmann B, Pallauf J
DTW Dtsch Tierarztl Wochenschr 1997 Aug 104:8 291-4
Abstract
In 21 farms which requested consultation for reasons of infertility
problems feed samples (grass silage, n = 20; cornsilage, n = 19; hay, n
= 9; cereal mixture, n = 3, brewers grains, n = 5, ensiled sugar beet
tops, n = 1) were drawn for assay of free (aglycon) and glycosidic
(glycosid) bound oestrogen activity.
Following sample preparation and extraction, the oestrogenic
activity was determined using a radioreceptorassay and only those
samples leading to a 50% displacement of the 3H-estradiol-17
beta-tracer were classified as oestrogen-positive; values were
expressed as ng 17 beta-estradiol equivalents per g dry matter.
Selected samples clearly oestrogen-positive in the aglycone fraction
were submitted to separation by HPLC and cytograms were established
with the intention to allow an assignment of the oestrogenic activity
to the following reference compounds, coumestrol, genistein, daidzein,
formononetin, biochanin A, zeeralenon.
With regard to free oestrogenic activity (aglycon) most of the grass
silages were positive while-with one exception - the cornsilages were
negative as were the hay-samples. The brewers grain samples were
likewise positive and negative. Distinctly lower concentrations were
found for the glycosidic bound oestrogenic activity with highest levels
determined in hay.
Results obtained after application of HPLC showed that the
oestrogenic activity could particularly be attributed to daidzein and
biochanin A. In the only oestrogen-positive cornsilage-sample the
activity found corresponded with zearalenon.
Types and concentrations of the oestrogenic activity allow the
conclusion that negative effects on reproduction cannot be excluded.
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