INDUCTION OF PHYTOESTROGEN PRODUCTION IN MEDICAGO-SATIVA LEAVES BY IRRIGATION WITH SEWAGE WATER

The phytoestrogenic activity of alfalfa irrigated with sewage water wa s determined by radioreceptor assay (RRA) and high pressure liquid chr omatography (HPLC). It was found that irrigation of alfalfa fields inc reased the phytoestrogenic activity measured in the leaves from 10 ng estrogen equivalents test. eqv.) to 137 ng est. eqv. g(-1), which was principally due to a rise in coumestrol (<10 mu g to 60 mu g g(-1)). S imilarly, when plants grown in greenhouses under controlled conditions were irrigated with sewage water, the phytoestrogenic content rose fr om 34 to 48 est. eqv. g(-1); (P < 0.01; n = 16). Under hydroponic cond itions, addition of 1 nM of estrone to the media resulted in a signifi cant rise in phytoestrogen content in the leaves within 48 hr (from 21 .2 to 34.5 est eqv. g(-1); P < 0.05, n = 10). Alfalfa irrigated with s ewage water may therefore have levels of coumestrol (< 30 mu g g(-1)) which can affect fertility in cattle. The agents in the sewage water r esponsible for increased phytoestrogen content of the alfalfa are prob ably the steroidal estrogens, estradiol and estrone, which are present in sewage in concentrations ranging from 10 to 300 ng l(-1).