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Methoxychlor given in the periimplantation period blocks sexual arousal in male mice
S Y Amstislavsky1, T G Amstislavskaya, V P Eroschenko
1Novosibirsk State University, Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Division.
Abstract:
To determine whether pesticide methoxychlor (MXC) alters sexual arousal in male offspring, pregnant ICR mice remained untreated or received daily subcutaneous injections (s.c.) of olive oil, 33.0 mg/kg bw purified (95%) MXC, or 0.33 mg/kg bw estradiol-173 in vehicle on Days 5 to 7 of pregnancy. Live births were recorded in all groups except the estradiol group. At 4 months, untreated or olive oil-treated male offspring exhibited normal sexual arousal. When placed near a plastic partition with an estrus female behind it, these males spent significantly more time near the partition than near a vacant half of the cage and exhibited a sharp increase in plasma testosterone. MXC-exposed males showed no sexual arousal, spent much less time near the partition with an estrus female, and exhibited significantly lower plasma testosterone levels. Exposure to purified MXC close to implantation alters the function of the hypothalamic-pituitary-testicular axis and compromises male sexual behavior in offspring.
Insights
Pesticide methoxychlor (MXC) exposure during pregnancy significantly impairs sexual arousal and lowers testosterone levels in male offspring. This endocrine disruptor affects the hypothalamic-pituitary-testicular axis, compromising reproductive health.
Area of Science:
- Endocrinology
- Reproductive Toxicology
- Developmental Biology
Background:
- Methoxychlor (MXC) is an organochlorine pesticide with known endocrine-disrupting properties.
- Prenatal exposure to environmental contaminants can have long-lasting effects on reproductive health.
- The hypothalamic-pituitary-testicular (HPT) axis is crucial for male sexual development and function.
Purpose of the Study:
- To investigate the effects of prenatal methoxychlor (MXC) exposure on sexual arousal in male offspring.
- To determine if MXC exposure alters testosterone levels in adult male offspring.
- To assess the impact of MXC on the functionality of the HPT axis.
Main Methods:
- Pregnant ICR mice were administered methoxychlor (MXC) or estradiol-17β via subcutaneous injection during Days 5-7 of gestation.
- Male offspring were assessed for sexual behavior (arousal) and plasma testosterone levels at 4 months of age.
- Behavioral assessments included proximity to a receptive female and hormonal level measurements.
Main Results:
- Male offspring prenatally exposed to MXC exhibited significantly reduced sexual arousal compared to controls.
- MXC-exposed males showed markedly lower plasma testosterone levels.
- Control and vehicle-treated males displayed normal sexual arousal and elevated testosterone levels.
Conclusions:
- Prenatal exposure to methoxychlor (MXC) disrupts the hypothalamic-pituitary-testicular axis in male offspring.
- MXC exposure during early pregnancy compromises male sexual behavior and reproductive function.
- These findings highlight the potential risks of endocrine-disrupting pesticides on male reproductive health.
