In utero exposure to diesel exhaust increased accessory reproductive gland weight and serum testosterone concentration in male mice.

The effects of in utero exposure to diesel exhaust (DE) on the male mouse reproductive system were examined. Pregnant ICR mice inhaled DE at soot concentrations of 0.3, 1.0, or 3.0 mg DEP/m3 or clean air as the control, for 2-16 days postcoitum. On postnatal day (PND) 28, the weights of the testes and accessory glands and testosterone concentration in serum were significantly higher in the DE-exposed male pups. Testosterone concentration correlated significantly (P<0.01) with the expression levels of steroidogenic enzyme mRNAs, weights of the testes and male reproductive accessory glands, and daily sperm production. These findings indicate that very early stage mouse embryo exposure to DE leads to endocrine disruption after birth and acceleration of male puberty.