Table 2. Environmental toxicants that affect steroidogenesis.

Toxicant	Dose and duration	Observed effects	Reference
Aroclor 1254	In vitro exposure at 10−7, 10−8, 10−9, 10−10 mol l−1 for 24 h under basal and LH-stimulated conditions	Decreased LH-stimulated testosterone production, decreased activity of antioxidant enzymes and steroidogenic enzymes	92
Bisphenol A	Subcutaneous injection of 20, 100 or 200 mg kg−1 day−1 for 6 weeks	Decreased plasma levels of testosterone and LH, cholesterol carrier protein and steroidogenic enzymes and decrease numbers of Leydig cells	83
Endosulfan	Oral administration of 1 mg kg−1 body weight for 30 days	Decreased activity of steroidogenic enzymes and 3β-hydroxysteroid dehydrogenase	72
Atrazine	Oral gavage of 50, 200 mg kg−1 for 15 days or 300 mg kg−1 for 7 days	Decreased plasma and testicular testosterone levels, 3β-hydroxysteroid dehydrogenase and aryl hydrocarbon receptor expression	93
Fenvalerate	Oral administration of 60 mg kg−1 body weight from postnatal day 35 to PND 63	Decreased testosterone biosynthesis, downregulated expression of P-450scc and 17α-hydroxylase cytochrome P-450	94
Benzopyrene	Inhalation of 5, 75 or 100 µg benzopyrene m−3, 4 h daily for 10 days	Decreased plasma testosterone levels	95
Prochloraz	31.3, 62.5 or 125 mg kg−1 day−1 postnatal day 23 to 42 or 51	Decreased serum testosterone levels	96

LH, luteinizing hormone.