Effects of bis(2-ethylhexyl) phthalate, γ-hexachlorocyclohexane, and 17β-estradiol on the fry stage of medaka (Oryzias latipes).
The effects of bis(2-ethylhexyl) phthalate (DEHP), γ-hexachlorocyclohexane (γ-HCH), and 17β-estradiol (E2) on the fry stage of medaka were investigated. The medaka fry were exposed to different concentrations (0.01, 0.1, 1, and 10μg/L) of these chemicals for 3 weeks after hatching. Then, mortality, body weight, sex ratio, and gonadosomatic index (GSI) of the matured fish (after 5 months) were measured. Mortality was increased significantly in the 10μg/L E2 group. Distortion of sex ratio was found in 1 and 10μg/L E2 groups. DEHP treated groups showed the GSI reduction only in male fish. All the γ-HCH and parts of the E2 treated groups showed the GSI reduction in both sexes. Exposure of DEHP, γ-HCH, and E2 during the fry stage affected normal maturation of medaka at the concentrations which had no impact on mortality or sex ratio.
Long‐term exposure to bis(2‐ethylhexyl)phthalate (DEHP) inhibits growth of guppy fish (Poecilia reticulata)
Bis(2‐ethylhexyl)phthalate (DEHP) is a widely used plasticizer that is a commonly found contaminant of aquatic environments. However, little is known about the long‐term effects of DEHP on fish development, as previous studies yielded conflicting results and mostly investigated the effects of concentrations higher than those found in natural habitats. We thus aimed to investigate the effects of DHEP (i) at concentrations present in the environment, and (ii) under conditions that might accentuate any deleterious consequences (larvae rather than adult fish, use of higher temperature). Different concentrations of DEHP (0.1–10 µg l−1rpar; applied continuously for 91 days were tested on guppy fish that were less than one week old at the beginning of the treatment. As early as 14 days after the start of exposure, guppies treated with 10 µg l−1 DEHP showed significantly reduced body length as compared with control fish. The inhibitory effect of DEHP was concentration‐dependent and increased with time, leading to a maximal reduction in body length of 15 and 40% at 1 and 10 µg l−1 DEHP, respectively. The effect was even more pronounced for body weight, which was diminished by up to 40 and 70% at 1 and 10 µg l−1 DEHP, respectively. The reduction in growth was still significant at 91 days of DEHP treatment, whereas the Fulton's condition factor was unaffected. While DEHP significantly blocked growth in both male and female guppies, no shift in the sexual development was observed. These data show that DEHP, at concentrations present in aquatic environments, can profoundly affect development in fish. Copyright © 2009 John Wiley & Sons, Ltd.
Hepatic effects of phthalate esters.
Di(2-ethylhexyl) phthalate (DEHP), a commonly used plasticizer and microchemical environmental pollutant, produces subtle changes in hepatic function as judged by increase in liver weight and morphological and biochemical alterations. It can modify the biological response of drugs and other xenobiotics. Such interactions appear to occur at the pharmacokinetic phase, as DEHP was found to alter the activity of microsomal drug-metabolizing enzymes and ethanol metabolism. DEHP produced a time- and route-dependent effect on the hepatic cytochrome P-450 contents and activity of aminopyrine N-demethylase, aniline hydroxylase, alcohol dehydrogenase and high and low Km aldehyde dehydrogenases when given orally or intraperitoneally. Under in vitro conditions, DEHP produced no effect on the activity of aminopyrine N-demethylase or aniline hydroxylase, while mono(2-ethylhexyl) phthalate (MEHP) and 2-ethylhexanol (2-EH) significantly inhibited their activity at concentrations ranging from 2.5 to 15.0 mM. Activity of aminopyrine N-demethylase and aniline hydroxylase was also inhibited by dimethyl phthalate (DMP) and dibutyl phthalate (DBP) after a single oral administration. In view of the possibility of the human exposure to phthalates and other xenobiotics simultaneously, these observations are of great significance.