Assessing the consequences of the pesticide methoxychlor: neuroendocrine and behavioral measures as indicators of biological impact of an estrogenic environmental chemical.

Japanese quail provide an advantageous avian model for assessing long-term biological consequences of endocrine disrupting chemicals (EDCs). These studies examined route of exposure and vulnerability to biological impact of EDCs over the life cycle in a precocial avian model, the Japanese quail. Embryonic exposure occurs with maternal deposition and methoxychlor (MXC) accumulated with maternal exposure. Egg injections of MXC or estradiol at selected stages of development impacted hypothalamic neuroendocrine systems in hatchlings and affected sexual maturation, with evidence for long-term effects on neurotransmitters and male behavior. Two-generation dietary studies were conducted to examine transgenerational effects of EDCs. Adult quail (P1) were exposed to dietary MXC (0, 0.5 and 5 ppm), with continued exposure in their offspring (F1), and control diet for all F2 chicks. Toxicological end points, including fertility, hatching success, and 14-day viability were unaffected. F1 and F2 male offspring from MXC-treated pairs MXC had impaired mating behavior and altered plasma hormones. These studies confirm neuroendocrine and behavioral measures as reliable indices of exposure to an estrogenic EDC. Moreover, maternal deposition remains a primary route of EDC exposure, with potential deleterious consequences for field birds, especially precocial species that appear to be particularly sensitive to embryonic EDC exposure.

Effects of dose and glycosylation on the transfer of genistein into the eggs of the Japanese quail (Coturnix japonica).

Soy isoflavones have been associated with several beneficial effects of soy in human diets. However, most soy is consumed by livestock in the Western countries. It is possible that isoflavones could be transferred and/or accumulated into animal products, which could become additional sources of dietary isoflavones for humans. Our objectives were to determine whether dietary isoflavone genistein could be transferred and/or accumulated into the eggs of Japanese quail (Coturnix japonica) and how the supplementation dosage and glycosylation of the isoflavone would affect this transfer. Adult reproductive female Japanese quail were randomly assigned to treatment groups that received encapsulated 50 or 100 mg genistein or 80 mg genistin per day (four quail per treatment) for 5 days. A control group (two quail) received placebo capsules. Eggs were collected prior to treatment and then daily for 15 days. The egg, separated into yolk and white, and pulverized quail diet were extracted in 80% methanol for 2 h and either centrifuged or filtered before evaporation of the solvent. The extracts were redissolved in 16% acetonitrile for high-performance liquid chromatography (HPLC) analyses. Genistein and genistein metabolites were detected in the egg yolks of treated quail. Trace concentrations of genistein were detected in the control group, due to the presence of genistein derivatives in the diet. Neither genistein nor its metabolites were found in egg white. Levels of genistein in the eggs increased significantly from the 3rd day of supplementation and reached the maximum about 2 days after the supplementation stopped. The higher dose of genistein supplementation resulted in higher genistein concentrations in egg yolks. Glycosylation decreased the transfer and accumulation of genistein into the egg yolks.