Leucaena leucocephala extract has estrogenic and antiestrogenic actions on female rat reproduction

Leucaena feed has been reported to cause disruptive effects on livestock reproduction, such as low calving percentages in cows, abortion in female goats and pigs, dead fetuses and fetal resorption in pregnant rats. In this study, the effects of Leucaena on different female reproductive variables were analyzed in two different reproductive conditions: gonadally intact and ovariectomized (OVX) female rats. Leucaena (LEU) was administered to females in both experimental conditions for 30 consecutive days. The effects of the legume extract were compared with those of Daidzein (DAI), a phytoestrogen, and of the female hormone estradiol (E₂). In intact females, LEU disrupted the estrous cycle and female sexual behavior, decreased the number of follicles and corpora lutea, increased uterine and vaginal epithelium in proestrus and diestrus periods, increased uterine and vaginal relative weights during diestrus, and decreased serum progesterone during proestrus. All these effects were similar to those of DAI but lower than E₂-induced effects. In OVX females, LEU decreased body weight, induced lordosis, stimulated vaginal epithelium cornification, increased vaginal weight, and augmented vaginal epithelium thickness. Again, these effects were similar to the effects of DAI and lower than the effects observed with E₂. These results indicate that, in gonadally intact females, LEU can produce antiestrogenic effects in sexual behavior but estrogenic effects on uterine and vaginal weight and epithelia, without modifying serum levels of E₂. In OVX females, in total absence of endogenous E₂, LEU induced estrogenic effects on vaginal weight and epithelia, as well as on sexual behavior.