Estrogens biological effects

Vethaak, A.D., Lahr, J., and Schrap, S.M. et al. (2005). An integrated assessment of estrogenic contamination and biological effects in the aquatic environment of the Netherlands. 

Phytoestrogens may elicit their biological effects by binding to estrogen receptors (ERs). Until recently, only a single ER isoform, ERa, had been identified however, a second receptor termed ERp has also been identified (Enmark et al, 1997, 1999 Saunders et al, 2000, 2001). It has been shown that the ERs have different intracellular and tissue distribution patterns and are responsible for different biological effects (see Table 5.1). A number of spliced variants of both ERa and ERp have also been identified (Inoue et al, 2000 Ogawa et al, 1998 Vladusic et al, 1998). 

The spectrum of llavonoid biological effects is very broad the best known are their estrogenic, antitumor, antimicrobial, antiallergic, and antiinflammatory activities (for review, see Cushnie [19]). At least some of these activities are based on non-membrane-related mechanisms, like flavonoid-induced cell cycle arrest. Most of them, however, are claimed in the literature to appear as a consequence of antioxidative properties of flavonoids. 

There has been considerable interest in characterizing the biological effects of NP and related alkyl-phenols, ever since some were reported to exhibit estrogenic activity. Structure-activity studies with al-kylphenols have shown clearly that the branching pattern, length of carbon chain, and substitution patterns on the phenolic ring have dramatic effects on the biological activity. 

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