The hop phytoestrogen, 8-prenylnaringenin, reverses the ovariectomy-induced rise in skin temperature in an animal model of menopausal hot flushes.
نویسندگان
چکیده
The mechanisms underlying menopausal hot flushes are poorly understood, although it is generally assumed they result from disturbances of thermoregulatory centres in the hypothalamus. 8-Prenylnaringenin (8-PN) has been identified as a potent phytoestrogen in hops (Humulus lupulus) and there are claims that hop-containing preparations can reduce hot flushes. We have investigated the site of action of 8-PN in a rat model of menopausal hot flushes, in which the tail skin temperature (TST) is increased after oestrogen withdrawal induced by ovariectomy. Daily s.c. administration of either 17beta-oestradiol (E2; 4 microg/kg) or 8-PN (400 microg/kg) significantly reduced the elevated TST after 2 days of treatment. Subcutaneous co-administration of either E2 or 8-PN with the oestrogen receptor (ER) antagonist, ICI 182,780 (200 microg/kg), which is thought not to cross the blood-brain barrier, completely blocked the effect of E2 and 8-PN on TST. The ERalpha- and ERbeta-specific agonists, 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (100 microg/kg) and 2,3-bis(4-hydroxyphenyl)-propionitrile (60 microg/kg) respectively, both significantly reversed the raised TST in ovariectomised rats. These observations suggest that the regulation of the vasomotor response by oestrogens and phytoestrogens is mediated, at least in part, by peripheral mechanisms involving both ERalpha and ERbeta.
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تأثیر رازک بر نشانه های زودرس یائسگی در زنان پست منوپوز: یک کارآزمایی بالینی دوسوکور کنترل شده
Background: Of common alternative treatments for early symptoms of early menopause are phytoestrogens. Phytoestrogenic compounds naturally occur in hop, though there is no study investigating the hop effect on the early symptoms of menopause. This study aims to evaluate the effect of hop (Humulus lupulus L.) in treating early menopausal symptoms and hot flashes (primary outcomes). Metho...
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Hop extract is a long used medicinal product and, regarding hormonal activities, in 1999 a number of prenylflavanones have been identified as its major constituents with 8-prenylnaringenin (8-PN) being the main active estrogenic compound. There have been several in vivo studies performed that demonstrate the potential of hop extract and the single compound 8-PN to alleviate climacteric symptoms...
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Menopausal hot flushes (HFs), which manifest as a transient increase in skin temperature, occur most frequently in postmenopausal women, and sometimes negatively influence daily life. We investigated the effect of an aqueous extract of Cynanchum wilfordii (CWW) in a rat model of menopausal HFs, where tail skin temperature (TST) is increased after the rapid estrogen decline induced by ovariectom...
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Objectives: Ovariectomy of young rodents is the most frequently used animal model of the menopause. However, the assumption that ovariectomy, causing a rapid loss of ovarian hormones is a general model of menopause in not well supported. Several animal models have been developed with the aim of mitigating the human conditions of the menopause. Among these, the ovotoxin 4-vinylcyclohexene diepox...
متن کاملElevation of tail skin temperature in ovariectomized rats in relation to menopausal hot flushes.
Menopausal hot flushes (HFs), which manifest as an increase in skin temperature, most frequently occur after menopause and cease with the passage of time. We designed this study to elucidate the characteristics of the elevation of tail skin temperature (TST) in ovariectomized (OVX) rats, which is relevant to human symptoms of HFs. First, we measured TST and rectal temperature (RT) and investiga...
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ورودعنوان ژورنال:
- The Journal of endocrinology
دوره 191 2 شماره
صفحات -
تاریخ انتشار 2006