Any physiological, developmental, or behavioral process that is controlled by the endocrine system can be altered by endocrine disrupting chemicals (EDCs). EDCs are ubiquitous pollutants, and humans are commonly exposed to concentrations that induce human health problems including birth defects. For example, penis deformities are the most common birth defect occurring in boys born in several states, and many are associated with prenatal exposure to EDCs. Hypospadias occurs when the urethra does not open at the distal tip of the penis but rather somewhere along its shaft. As many as 1% of boys are born with this penis deformity and many suffer painful erections, reduced fertility, difficulty with urination, and lasting negative psychological effects. Treatment options range from difficult corrective surgery to sexual reassignment. The high incidence of pollutant-induced genital birth defects coupled with the difficulties associated with corrective surgery, and negative long-term outcomes indicate the need for rapid progress in developing treatments that reduce severity and incidence of penis defects. Epidemiological studies suggest prenatal vitamin supplementation decreases hypospadias risk, but this has not been experimentally tested, and the specific supplements and mechanisms driving this protection are unknown. We recently determined that pollutant exposed fetuses supplemented with natural phytochemicals, have rescued penis development relative to embryos exposed to only pollutants. This project will determine the mechanisms driving these rescue effects. Pregnant female mice will be exposed to four treatments (pollutant, pollutant+supplement, supplement alone, and control). First, we test the hypothesis that prenatal nutritive supplementation increases detoxifying enzymes within mother and fetal livers and decreases toxicant body burden. Livers will be collected from dams and embryos and gene and protein quantity of detoxifying enzymes and drug transporters will be measured. Maternal serum and embryo carcasses will be used to determine toxicant concentrations. Genitiala from the embryos will be morphologically evaluated to determine hypospadias severity. We will evaluate the relationship between changes in detoxifying enzymes and toxicant body burden, and relate those measures to hypospadias severity. Next, we will test the hypothesis that prenatal nutritive supplementation of toxicant exposed fetuses increases endogenous antioxidants and steroidogenic enzymes within the testes, increasing circulating androgen concentrations which are required for normal penis formation. Fetal carcasses will be used to determine whole body testosterone concentrations. We will identify the mechanisms through which supplementation decreases oxidative stress and increases steroidogenesis and androgen quantity, and then link those measures with hypospadias severity. Results will facilitate the development of a treatment to protect the developing fetus from toxicants, and to reduce the incidence and severity of hypospadias, the most common birth defect in boys born in the U.S.A.
This project will contribute fundamental knowledge that will aid in the development of a prenatal nutritive supplement that will reduce the severity and incidence of the most common birth defect occurring in boys born in the United States.