Effects of intracerebroventricular infusion of genistein on gonadotrophin subunit mRNA and immunoreactivity of gonadotrophins and oestrogen receptor-α in the pituitary cells of the anoestrous ewe

Polkowska, Jolanta; Ridderstråle, Yvonne; Wańkowska, Marta; Romanowicz, Katarzyna; Misztal, Tomasz; Madej, Andrzej

doi:10.1016/j.jchemneu.2004.07.004

Cited by 17 publications

(13 citation statements)

References 32 publications

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“…Whereas both the GnRH-inhibited effect of coumestrol and selective endocrine activity of genistein (an isoflavone) led to reducing LH release at the level of rat pituitary [17, 18], high-dose administration of dietary equol (another isoflavone metabolite) markedly enhanced serum LH level in the ovariectomized rat [19], and intracerebroventricular of ganister increased the percentage of LHβ-subunit gene expressing cells in the anoestrous ewe pituitary via activation of cellular ERα [20]. FSH is another kind of gonadotropin released from the pituitary.…”

Section: Discussionmentioning

confidence: 99%

“…FSH is another kind of gonadotropin released from the pituitary. Genistein had no effect either on FSH cellular immunoreactivity or on the FSHβ gene expression possibly due to no ERα existence on FSH-gonadotrophs in ewe [20]. Dichotomal phenomenon of phytoestrogen on gonadotropin secretion has been also detected in a clinical study of postmenopausal women: mean LH release decreased after discontinuing dietary isoflavone intake, but one of these women was observed to have a higher LH secretion after treatment [21].…”

Section: Discussionmentioning

confidence: 99%

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Phytoestrogen Biological Actions on Mammalian Reproductive System and Cancer Growth

Zhao

Mu²

2011

Sci. Pharm.

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Phytoestrogens are a family of diverse polyphenolic compounds derived from nature plant that structurally or functionally mimic circulating estrogen in the mammalian reproductive system. They induce estrogenic and anti-estrogenic effects in the brain-pituitary-gonad axis (a principal endocrine system involving in reproductive regulation) and peripheral reproductive organs. The dichotomy of phytoestrogen-mediated actions elucidates that they play the biological activities via complex mechanisms and belong to various chemical classes. In comparison with their unobvious physiological functions in normal reproductive tissues, there are increasing investigations showing that phytoestrogen induces significant inhibitory effects on the growth of breast and ovarian cancers through different signaling pathways. This review summarized the results of the previous studies regarding principal signaling transductions for mediating the growth of the ovarian and breast cancers. Phytoestrogen potentially modulates the signaling molecules via: (1) blocking the nuclear and membrane estrogen receptors (ER), (2) interfering with the growth factor receptor, (3) inhibiting the G protein-coupled receptor in ER-deficient cells, (4) activating apoptosis and nullifying anti-apoptotic signals.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Phytoestrogen Biological Actions on Mammalian Reproductive System and Cancer Growth

Zhao

Mu²

2011

Sci. Pharm.

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“…Maeng et al [27 ]reported that NP induced the LHβ mRNA without affecting FSHβ mRNA in the pituitary of masu salmon. In addition, genistein, a phytoestrogen, only affected the expression of LHβ and its mRNA, but not FSHβ in the ewe [28]. Basically, estrogen regulation of LHβ mRNA is more robust than that of FSHβ [29].…”

Section: Discussionmentioning

confidence: 99%

Effects of <i>p</i>-Nonylphenol and 4-<i>tert</i>-Octylphenol on the Anterior Pituitary Functions in Adult Ovariectomized Rats

Furuta

Funabashi²,

Kawaguchi³

et al. 2006

Neuroendocrinology

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p-Nonylphenol (NP) and 4-tert-octylphenol (OP) are known to mimic the action of estrogens as endocrine disruptors. However, their acute effects on the pituitary and the hypothalamus functions in vivo have been uncertain. We therefore determined their effects on the anterior pituitary, in particular, gonadotropin secretion. Two weeks after ovariectomy, the rats were given a subcutaneous injection of 10 mg NP, 10 mg OP, 10 mg bisphenol A, 1 µg 17β-estradiol, or sesame oil alone as control. Twenty-four hours after the treatment, the expression of progesterone receptor mRNA in the anterior pituitary and the level of luteinizing hormone (LH), follicle-stimulating hormone, and prolactin were determined. The expression of progesterone receptor mRNA in the anterior pituitary was significantly increased by either NP, OP, bisphenol A, or estradiol, but bisphenol A was less effective. The level of LH was significantly decreased by either NP or OP, but not by bisphenol A and estradiol. Only estradiol significantly increased the level of prolactin. The level of follicle-stimulating hormone was unchanged by any of the treatments. To check the effects of NP and OP on pulsatile LH secretion, blood samplings were done at 6-min intervals for 3 h. Twenty-four hours after treatment in ovariectomized adult rats, we found that the injection of NP significantly decreased the amplitude of LH pulses and the mean LH concentrations, but not the frequency of LH pulses. The injection of OP significantly decreased the mean LH concentrations without affecting the frequency and amplitude of the LH pulses. Finally, the rats given an injection of NP or sesame oil were intravenously injected with 50 ng of gonadotropin-releasing hormone (GnRH) to check whether NP affected the LH secretory responsiveness of the anterior pituitary to GnRH. We found that the responsiveness to GnRH in NP-injected rats was significantly attenuated compared to the sesame oil-injected rats. The present study suggests that NP, even with a single injection, suppresses the pulsatile LH secretion in adult ovariectomized rats, probably by affecting the anterior pituitary level.

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“…Polkowska et al [48] found that genistein infused to the third ventricle of the brain changed the endocrine activity strictly of LH-producing cells in the pituitary glands of ewes during the anoestral season. However, the infusion of genistein did not affect the expression of genes encoding FSH β and the storage of the β -subunit in the FSH-producing cells.…”

Section: Adverse Effects Of Isoflavones On the Reproductive Performentioning

confidence: 99%

“…These results suggest that probably a rapid release of the hormone together with an enhanced synthesis of LH is possibly mediated by ER α . Data obtained by Polkowska et al [48] implicated that genistein stimulated the expression of ER α in the LH β -expressing cells, decreased the pool of secretory granules stored in the LH-producing cells, and augmented the synthesis of β subunit for LH. Misztal et al [49] analysed the effect of intracerebroventricularly genistein administration on growth hormone (GH) secretion in ewes.…”

Section: Adverse Effects Of Isoflavones On the Reproductive Performentioning

confidence: 99%

Diverse Effects of Phytoestrogens on the Reproductive Performance: Cow as a Model

Wocławek-Potocka

Mannelli

Boruszewska

et al. 2013

International Journal of Endocrinology

104

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Phytoestrogens, polyphenolic compounds derived from plants, are more and more common constituents of human and animal diets. In most of the cases, these chemicals are much less potent than endogenous estrogens but exert their biological effects via similar mechanisms of action. The most common source of phytoestrogen exposure to humans as well as ruminants is soybean-derived foods that are rich in the isoflavones genistein and daidzein being metabolized in the digestive tract to even more potent metabolites—para-ethyl-phenol and equol. Phytoestrogens have recently come into considerable interest due to the increasing information on their adverse effects in human and animal reproduction, increasing the number of people substituting animal proteins with plant-derived proteins. Finally, the soybean becomes the main source of protein in animal fodder because of an absolute prohibition of bone meal use for animal feeding in 1995 in Europe. The review describes how exposure of soybean-derived phytoestrogens can have adverse effects on reproductive performance in female adults.

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Effects of intracerebroventricular infusion of genistein on gonadotrophin subunit mRNA and immunoreactivity of gonadotrophins and oestrogen receptor-α in the pituitary cells of the anoestrous ewe

Cited by 17 publications

References 32 publications

Phytoestrogen Biological Actions on Mammalian Reproductive System and Cancer Growth

Phytoestrogen Biological Actions on Mammalian Reproductive System and Cancer Growth

Effects of <i>p</i>-Nonylphenol and 4-<i>tert</i>-Octylphenol on the Anterior Pituitary Functions in Adult Ovariectomized Rats

Diverse Effects of Phytoestrogens on the Reproductive Performance: Cow as a Model

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