Endocrine Abstracts

Studies on breast cancer cell lines, placental microsomes and purified recombinant enzymes have shown that various phytoestrogens can inhibit both aromatase and 17beta-hydroxysteroid dehydrogenase (HSD) enzymes. This has led to the suggestion that certain phytoestrogens may exert their endocrine disrupting functions by enzyme inhibition rather than their ability to bind weakly to oestrogen receptors. Previous studies have shown that genistein, the active ingredient of soy, ind...

Numerous investigations have shown that FSH can induce aromatase in granulosa cells obtained from natural ovarian cycles. In contrast granulosa luteal (GL) cells obtained from patients undergoing procedures for IVF are generally insensitive to FSH-induction of aromatase. A few studies, however, have reported that GL cells can be sensitized to this gonadotrophin. In these experiments we compared the conversion of various steroid substrates - namely pregnenolone and androstenedi...

Phytoestrogens (PEs) have a weak affinity for the oestrogen receptor. There is, however, no consistent evidence that, on a normal diet, circulating levels of PEs reach sufficient concentrations to exert significant oestrogenic/anti-oestrogenic effects. Phytoestrogens have been implicated in other cellular actions, not all of which necessarily involve the oestrogen receptor. Studies on cell-free systems and cell lines have demonstrated dose-dependent inhibitory effects of PEs o...