The effect of genistin and its aglycone on weight gain in the mouse

The observations that reproductive disturbances occurring in sheep grazing subterranean clover pastures were associated with the oestrogenic activity of the plant (Bennetts, 1944; Bennetts, Underwood & Shier, 1946; Curnow, Robinson & Underwood, I 948) stimulated interest in compounds, other than those normally classified as nutrients occurring in plants, that may have an effect on the performance of animals.These observations, coupled with the isolation and identification of genistein (5, 7, 4'-trihydroxyisoflavone) as the compound in subterranean clover mainly responsible for its oestrogenic activity, gave rise to investigations into the soya-bean plant, since soya-bean meal contains genistin, the 7-glucoside of genistein (Walter, 1941)) and reproductive disturbances had been reported in sheep and rabbits receiving soya-bean forage (Kendall, Salisbury & Vandemark, 1950; Schaub & Baver, 1944; Hunt, 1935).Soya-bean meal, genistin and the aglycone genistein, isolated and prepared from soya-bean meal, were subsequently found to be oestrogenically active (Carter, Smart & Matrone, 1953; Cheng, Story, Yoder, Hale & Burroughs, 1953; Carter, Matrone & Smart, 1955).Genistin has also been shown to affect reproduction of the mouse adversely (Carter et al. 1955) and at somewhat higher levels to depress growth (Matrone, Smart, Carter, Smart & Garren, 1956).The objective of our study was to determine if the effects of genistin and genistein on growth are a result of their oestrogenic properties.To that end the growth-depressing effect, as reflected by weight changes in immature mice, of genistin and genistein prepared from soya-bean meal has been compared with that of stilboestrol and of oestradiol. E X P E R I M E N T A LTwo levels of genistein were compared with several levels of oestradiol and stilboestrol, but only one level of genistin was used, since the response curve for genistin at various levels had been investigated previously by us (Matrone et al. 1956).The levels used in the experiment were chosen so that the changes in body-weight were in the range of the linear log-dose relationship, in order to take advantage of well-known principles of bioassay.The basal diet was the same in composition as that of Matrone et al. (1956).