In vivo profiling of 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced estrogenic/anti-estrogenic effects in female estrogen-responsive reporter transgenic mice.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), commonly referred to simply as "dioxin", is a persistent environmental pollutant. Because of its high environmental persistence and biological accumulation, humans and animals are often exposed to TCDD. Therefore, the harmful effects on humans and animals is a major concern. Although studies have elucidated the adverse estrogenic and anti-estrogenic effects of TCDD, it is unclear in which tissues TCDD exerts these effects in vivo. To investigate the estrogen-related effects of TCDD in various tissues, we generated an improved estrogen-responsive reporter transgenic mouse in which the luciferase gene luc2 is expressed in response to estrogenic signals. Using these mice, we clarified that TCDD inhibits estrogenic signaling in liver and kidney but enhances estrogenic signaling in the pituitary gland in the same individual. Expression of aryl hydrocarbon receptor, aryl hydrocarbon receptor nuclear translocator, and estrogen receptor alpha mRNA was detected in liver, kidney, and pituitary gland, suggesting that the effects of TCDD on estrogenic signaling in these organs is independent of the expression pattern of these receptors. Thus, our results indicate that TCDD exerts both estrogenic and anti-estrogenic tissue-specific effects within the same individual.

Potential Interference of Oil Vehicles on Genital Tubercle Development during the Fetal Period in ICR Mice.

Corn oil, sesame oil, and 10% ethanol in corn oil are commonly used as dosing vehicles in toxicology studies. Since these vegetable oils contain bioactive compounds, it is important for toxicology studies to characterize the toxicities of the dosing vehicles themselves. It has been recently proposed that the width of the genital tubercle (GT), the dorsal-ventral length (D-V length) of the GT, and urethral tube closure in mouse fetuses can be used as novel markers for monitoring sexual development in mice. However, how these parameters are influenced by the dosing vehicles themselves remains unclear. Therefore, we evaluated the effects of corn oil, sesame oil, and 10% ethanol in corn oil on GT width, D-V length, and GT morphology in ICR mice. Our results showed that all three vehicles influenced GT width and D-V length, but not GT morphology, suggesting that the effects of dosing vehicles themselves might need to be considered when GT width or D-V length is used as a parameter to evaluate the effects of chemicals on GT development.

The antianxiety-like effect of astaxanthin extracted from Paracoccus carotinifaciens.

Astaxanthin is a red carotenoid pigment and is widely found in living organisms. Astaxanthin has a potent antioxidative ability and has been reported as having various biological effects on the central nerve system, such as a protective effect against ischemia/reperfusion injury and improvement in cognitive function. In this study, to investigate the effects of astaxanthin on anxiety and depression, we performed some behavioral trials including the elevated plus maze test, hole-board test, forced swim test, and tail suspension test. Astaxanthin (100 and 300 mg/kg/day for 10 days, p.o.) significantly increased the time spent in open arms in the elevated plus maze test and increased the head-dipping count and duration in the hole-board test. On the other hand, astaxanthin (10, 100, 300, and 500 mg/kg/day for 10 days, p.o.) did not change the immobility time in the forced swim test or the tail suspension test. In conclusion, in mice, astaxanthin exerted anxiolytic-like effects, but not antidepressant-like effects.