ABSTRACT
Prochloraz is a commonly used fungicide that has shown multiple mechanisms of action in vitro. It antagonizes the androgen and the estrogen receptors, agonizes the Ah receptor, and inhibits aromatase activity. In vivo prochloraz acts antiandrogenically in the Hershberger assay by reducing weights of reproductive organs, affecting androgen-regulated gene expressions, and increasing luteinizing hormone (LH) levels. The purpose of this study was to investigate reproductive toxic effects after exposure during gestation and lactation to prochloraz alone and a mixture of five pesticides (deltamethrin, methiocarb, prochloraz, simazine, and tribenuron-methyl). Prochloraz (30 mg/kg/day) or the mixture (20 mg/kg/day) was dosed to pregnant Wistar dams from gestational day (GD) 7 until postnatal day (PND) 16. Some dams were taken for cesarean section at GD 21, and others were allowed to give birth. Results showed that prochloraz and the mixture significantly reduced plasma and testicular testosterone levels in GD 21 male fetuses, whereas testicular progesterone was increased. Gestational length was increased by prochloraz. Chemical analysis of the rat breast milk showed that prochloraz was transferred to the milk. In males a significant increase of nipple retention was found, and the bulbourethral gland weight was decreased, whereas other reproductive organs were unaffected. In addition cytochrome P450 (CYP)1A activities in livers were induced by prochloraz, possibly as a result of Ah receptor activation. Behavioral studies showed that the activity level and sweet preference of adult males were significantly increased. Overall these results strongly indicate that prochloraz feminizes the male offspring after perinatal exposure, and that these effects are due, at least in part, to diminished fetal steroidogenesis.
Subject(s)
Animals, Newborn/physiology , Feminization/chemically induced , Fungicides, Industrial/toxicity , Imidazoles/toxicity , Animals , Behavior, Animal/drug effects , Cesarean Section , Cytochrome P-450 Enzyme System/metabolism , Female , Food Preferences/drug effects , Genitalia, Male/drug effects , Genitalia, Male/growth & development , Gonadal Steroid Hormones/blood , Habituation, Psychophysiologic/drug effects , Male , Maze Learning/drug effects , Milk/chemistry , Motor Activity/drug effects , Nipples/drug effects , Nipples/growth & development , Organ Size/drug effects , Play and Playthings , Rats , Rats, Wistar , Semen/cytology , Semen/drug effects , Sexual Maturation/drug effects , Taste/drug effectsABSTRACT
Di(2-ethylhexyl) phthalate (DEHP) is a well-known testicular toxicant inducing adverse effects in androgen responsive tissues. Therefore, di(2-ethylhexyl) adipate (DEHA) is currently being evaluated as a potential substitute for DEHP. Similarities in structure and metabolism of DEHP and DEHA have led to the hypothesis that DEHA can modulate the effects of DEHP. Wistar rats were gavaged with either vehicle, DEHP (300 or 750mg/kg bw/day) or DEHP (750mg/kg bw/day) in combination with DEHA (400mg/kg bw/day) from gestation day (GD) 7 to postnatal day (PND) 17. Decreased anogenital distance (AGD) and retention of nipples in male offspring were found in all three exposed groups. Dosed males exhibited decreased weights of ventral prostate and m. levator ani/bulbocavernosus. Histopathological investigations revealed alterations in testis morphology in both juvenile and adult animals. The litter size was decreased and postnatal mortality was increased in the combination group only, which is likely a combined effect of DEHP and DEHA. However, no combination effect was seen with respect to antiandrogenic effects, as males receiving DEHP in combination with DEHA did not exhibit more pronounced effects in the reproductive system than males receiving DEHP alone.
Subject(s)
Adipates/toxicity , Androgen Antagonists/toxicity , Diethylhexyl Phthalate/toxicity , Prenatal Exposure Delayed Effects , Sexual Maturation/drug effects , Administration, Oral , Animals , Body Weight/drug effects , Drug Synergism , Female , Genitalia, Male/drug effects , Genitalia, Male/growth & development , Genitalia, Male/pathology , Gestational Age , Male , Organ Size/drug effects , Pregnancy , Rats , Rats, Wistar , Sperm Count , Sperm Motility/drug effectsABSTRACT
In this study, mixture effects of five dissimilarly acting pesticides were analyzed for antiandrogenic effects in vitro and in vivo. Deltamethrin, methiocarb, prochloraz, simazine, and tribenuron-methyl are all commonly used for agricultural and horticultural purposes. Concentration-response curves for the inhibition of R1881-induced transcriptional activity of the androgen receptor (AR) in vitro of each pesticide alone and in an equimolar mixture were obtained. The IC25 values for deltamethrin, methiocarb, prochloraz, and the mixture were 5.8, 5.8, 3.5, and 7.5 microM, respectively. Simazine and tribenuron-methyl were ineffective. Applying the isobole method resulted in an isobole coefficient of 0.94 at IC25 for the effect of the mixture, indicating additive effects of the compounds. Comparison of observed effects and effects calculated by assuming additivity also strongly indicated additive effects of the pesticides in vitro. In vivo, each of the five pesticides and a mixture of the pesticides were tested for antiandrogenic effects in castrated testosterone-treated Wistar rats. The mixture induced a significant change of weights of the levator ani/bulbocavernosus muscle and adrenal glands. Changes in gene expression in ventral prostates were observed as distinct effects on levels of ornithin decarboxylase (ODC) mRNA and effects on levels of prostate binding protein subunit C3 (PBP C3) mRNA. No pesticide-induced effect on the level of testosterone-repressed prostatic message 2 (TRPM-2) mRNA was observed, whereas flutamide increased TRPM-2 levels. In conclusion, the pesticides were found to act additively in vitro. In vivo, the organ weight changes indicated that the pesticides had an accumulating effect that was not observed for the individual pesticides. Several pesticide-induced gene expression changes were observed, indicating that these are either very sensitive antiandrogenic end-points or that these changes are induced by a pathway not related to AR.
Subject(s)
Androgen Antagonists/toxicity , Genes, Reporter/drug effects , Pesticides/toxicity , Prostate/drug effects , Receptors, Androgen , Androgen Receptor Antagonists , Androgens , Animals , DNA, Complementary/biosynthesis , Dose-Response Relationship, Drug , Drug Interactions , Genes, Reporter/genetics , Male , Orchiectomy , Organ Size/drug effects , Prostate/metabolism , RNA/isolation & purification , Rats , Rats, Wistar , Reverse Transcriptase Polymerase Chain Reaction , Testosterone/bloodABSTRACT
Di(2-ethylhexyl) adipate (DEHA) has replaced the phthalates in thin plasticized polyvinyl chloride films used for food packaging, mainly because some phthalates induce testis toxicity and antiandrogenic effects. A dose-range finding study followed by a dose-response/effect study in Wistar rats investigated whether pre- and postnatal DEHA doses of 0, 800, or 1200mg/kg/day body weight and doses of 0, 200, 400, or 800mg/kg/day (main study) elicited developmental toxicity including antiandrogenic effects. In the main study, DEHA induced a prolonged gestation period (800mg/kg/day) and a dose-related increase in postnatal death (400 and 800mg/kg/day). DEHA also induced a permanent decrease in offspring body weight (800mg/kg/day). No antiandrogenic endpoints were affected. We conclude that DEHA induced developmental toxicity and the NOAEL is 200mg/kg. DEHA did not induce antiandrogenic effects similar to those of di(2-ethylhexyl) phthalate even though the chemical structures have similarities and the two chemicals have a common metabolite.
