Reproductive toxicology: the science today

Area of Science:

• Reproductive Toxicology
• Endocrinology
• Developmental Biology

Background:

• Reproductive toxicology investigates chemical and physical agents that impair fertility in both sexes.
• Adverse effects can stem from direct damage to reproductive tissues (e.g., semen-producing epithelium) or indirect disruption of sex hormone homeostasis.
• Critical developmental periods in utero and early postnatal life are vulnerable to irreversible defects caused by interfering agents.

Purpose of the Study:

• To review the mechanisms by which environmental agents can interfere with reproductive health.
• To highlight the importance of hormonal homeostasis and developmental imprinting in reproductive function.
• To discuss the complexities of assessing risks from environmental hormones ('ecohormones' or 'xenohormones').

Main Methods:

• Review of existing literature on reproductive toxicology, focusing on mechanisms of action.
• Analysis of direct and indirect effects on male and female reproductive systems.
• Consideration of developmental processes, hormonal regulation, and potential impacts of environmental agents.

Main Results:

• Disruptions during critical developmental windows (prenatal, perinatal, puberty) can lead to irreversible reproductive defects.
• Agents can cause feminization in males (e.g., via anti-androgens) or masculinization in females (via excess androgens).
• Adult reproductive function can be affected through direct receptor action or disruption of hormonal feedback mechanisms.

Conclusions:

• Environmental agents ('ecohormones') may pose risks by mimicking or inhibiting sex hormones, though clinical effects in the general population are debated.
• Species differences limit the predictive value of animal and in-vitro studies for human risk assessment.
• While widespread 'ecohormone' effects are uncertain, adverse impacts from extreme exposures (e.g., diet, overdose) cannot be ruled out.