Comparison of the phytohormones genistein, resveratrol and 8-prenylnaringenin as agents for preventing osteoporosis.

As the average age of society increases, identifying and preventing osteoporosis becomes more important. According to the results of the Women's Health Initiative study, substitution of estradiol is not recommended in hormone replacement therapy (HRT), although phytoestrogens might be a safe alternative. In this study, the osteoprotective effects of genistein (Gen), resveratrol (Res) and 8-prenylnaringenin (8PN) were evaluated by analysing bone biomechanical strength and bone mineral density.

Effects of long-term treatment with 8-prenylnaringenin and oral estradiol on the GH-IGF-1 axis and lipid metabolism in rats.

After the heart and estrogen/progestin replacement study and the women's health initiative study, the prospect of hormone replacement therapy (HRT) on cardiovascular diseases (CVD) has changed dramatically. These findings led to various attempts to search for alternatives for classical HRT, e.g.

Endocrine disruptors and the thyroid gland--a combined in vitro and in vivo analysis of potential new biomarkers.

Background: There is growing evidence that, in addition to the reproductive system, the hypothalamic-pituitary-thyroid axis is a target of endocrine-disrupting compounds (EDCs). However, this is not reflected adequately in current screening and assessment procedures for endocrine activity that to date determine only general parameters of thyroid function.

Objective And Methods: We used several in vitro and ex vivo assays in an attempt to identify suitable biomarkers for antithyroid action testing a selected panel of putative EDCs.

Effects of chronic genistein treatment in mammary gland, uterus, and vagina.

Background: The isoflavone genistein (GEN) is found in soy (Glycine max) and red clover (Trifolium pratense). The estrogenic activity of GEN is known, and it is widely advertised as a phytoestrogen useful in alleviating climacteric complaints and other postmenopausal disorders. Knowledge of effects of long-term administration of GEN in laboratory animals is scarce, and effects in the uterus and mammary gland after long-term administration have not been studied.

Morphologic changes induced by oral long-term treatment with 8-prenylnaringenin in the uterus, vagina, and mammary gland of castrated rats.

Objective: The flavonoid 8-prenylnaringenin (8-PN) is found in hops, and hence in beer, and is also increasingly consumed as a food supplement. It is the strongest known phytoestrogen, which makes it a good candidate as an alternative to hormone therapy. Its putatively undesired estrogenic effects in the uterus and mammary gland have not yet been thoroughly investigated.

Effects of long-term treatment with resveratrol and subcutaneous and oral estradiol administration on pituitary function in rats.

Hormone replacement therapy (HRT) has been used for several decades to treat menopausal discomforts. However, in the light of recent studies that draw attention to the potential hazards of conventional HRT, various attempts have been undertaken to search for alternatives to classical HRT. Phytoestrogens are claimed to be capable of positively influencing menopausal symptoms, including hot flushes.

Comparison of effects of estradiol with those of octylmethoxycinnamate and 4-methylbenzylidene camphor on fat tissue, lipids and pituitary hormones.

Octylmethoxycinnamate (OMC) and 4-methylbenzylidene camphor (4MBC) are commercially used absorbers of ultraviolet (UV) light. In rats, they were shown to exert endocrine disrupting including uterotrophic, i.e.

Effects of bisphenol-A (BPA), dibutylphtalate (DBP), benzophenone-2 (BP2), procymidone (Proc), and linurone (Lin) on fat tissue, a variety of hormones and metabolic parameters: a 3 months comparison with effects of estradiol (E2) in ovariectomized (ovx) rats.

The endocrine active substances BPA, DBP and BP2 have estrogenic effects in the uterus. Proc and Lin were shown to be antiandrogenic. Whether other estrogen-regulated parameters like lipids, fat metabolism and hormones are also affected by these substances is unknown.

Multi-organic endocrine disrupting activity of the UV screen benzophenone 2 (BP2) in ovariectomized adult rats after 5 days treatment.

The chemical industry has developed sun protection factor products, which contain a variety of so-called "UV screens", among others, benzophenones (BP). Based on the structure it can be assumed, that the variant BP2 may be a potent estrogenic endocrine disrupter (ED). Only very limited data are available in the literature about such action of BP2, which focussed on the uterotrophic effect in immature rats.