Soy Research Today is a free monthly online journal that collates and summarizes the latest research about Soy, including details on soy milk, soy protein, soya bean, benefits, dangers.

Effects of early embryonic exposure to genistein on male copulatory behavior and vasotocin system of Japanese quail.

Viglietti-Panzica C, Mura E, Panzica G

Laboratory of Neuroendocrinology, Neuroscience Institute of Torino (NIT), Department of Anatomy, Pharmacology and Forensic Medicine, University of Torino, Corso M. D’Azeglio 52, 10126, Torino, Italy.

Genistein is a phytoestrogen, particularly abundant in soybeans that can bind estrogen receptors and sex hormone binding proteins, exerting both estrogenic and antiestrogenic activity. In this study we used the Japanese quail embryo as a test end-point to investigate the effects of early embryonic exposure to genistein on male copulatory behavior and on vasotocin parvocellular system. Both differentiate by the organizational effects of estradiol during development and may therefore represent an optimal model to study the effects of xenoestrogens. We injected two doses of genistein (100 and 1000 mug) into the yolk of 3-day-old Japanese quail eggs. Other eggs were treated with either 25 mug of estradiol benzoate or sesame oil as positive and negative controls. At the age of 6 weeks, behavioral tests revealed a significant decrease of all aspects of copulatory behavior (in comparison to the control group) in estradiol-treated birds. In contrast, genistein-treated animals demonstrated various degrees of decrease in the mean frequencies of some aspects of the sexual behavior. The computerized analysis of vasotocin innervation in medial preoptic, stria terminalis and lateral septum nuclei revealed a statistically significant decreased immunoreactivity in treated animals compared to control ones. These results demonstrate that genistein, similarly to estradiol, has an organizational effect on quail parvocellular vasotocin system and on copulatory behavior. In conclusion, present results confirm, in this avian model, that embryonic exposure to phytoestrogens may have life-long effects on sexual differentiation of brain structures and behaviors.

Published 12 March 2007 in Horm Behav, 51(3): 355-363.
Full-text of this article is available online (may require subscription).

© 2004-2008 Soy Research Today. All Rights Reserved.