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Dibutyl phthalate (DBP) is recognized as an environmental endocrine disruptor that has been detected in fetal and postnatal samples. Recent evidence found that in utero DBP exposure was associated with an increase of adipose tissue weight and serum lipids in offspring, but the precise mechanism is unknown. Here we aimed to study the effects of in utero DBP exposure on obesity in offspring and examine possible mechanisms. SPF C57BL/6J pregnant mice were gavaged with either DBP (5 mg /kg/day) or corn oil, from gestational day 12 until postnatal day 7. After the offspring were weaned, the mice were fed a standard diet for 21 weeks, and in the last 2 weeks 20 mice were selected for TUDCA treatment. Intrauterine exposure to low-dose DBP promoted obesity in offspring, with evidence of glucose and lipid metabolic disorders and a decreased metabolic rate. Compared to controls, the DBP exposed mice had lower expression of UCP1 and significantly higher expression of Bip and Chop, known markers of endoplasmic reticulum (ER) stress. However, TUDCA treatment of DBP exposed mice returned these parameters nearly to the levels of the controls, with increased expression of UCP1, lower expression of Bip and Chop and ameliorated obesity. Intrauterine exposure of mice to low-dose DBP appears to promote obesity in offspring by inhibiting UCP1 via ER stress, a process that was largely reversed by treatment with TUDCA.

Background: A previous study showed that dibutyl phthalate (DBP) exposure disrupted the growth of testicular Sertoli cells (SCs). In the present study, we aimed to investigate the potential mechanism by which DBP promotes juvenile SC proliferation in vivo and in vitro., Methods: Timed pregnant BALB/c mice were exposed to vehicle, or DBP (50, 250, and 500 mg/kg/day) from 12.5 days of gestation until delivery. In vitro, CCK-8 and EdU incorporation assays were performed to determine the effect of monobutyl phthalate (MBP), the active metabolite of DBP, on the proliferation of TM4 cells, which are a juvenile testicular SC cell line. Western blotting analysis, quantitative PCR (q-PCR), and flow cytometry were performed to analyse the expression of genes and proteins related to the proliferation and apoptosis of TM4 cells. Coimmunoprecipitation was used to determine the relationship between the ubiquitination of interleukin 1 receptor-associated kinase 1 (IRAK1) and the effect of MBP on promoting the proliferation of TM4 cells., Results: In the 50 mg/kg/day DBP-exposed male mice offspring, the number of SCs was significantly increased. Consistent with the in vivo results, in vitro experiments revealed that 0.1 mM MBP treatment promoted the proliferation of TM4 cells. Furthermore, the data showed that 0.1 mM MBP-mediated downregulation of the E3 ubiquitin ligase Pellino 2 (Peli2) increased ubiquitination of IRAK1 by K63, which activated MAPK/JNK signalling, leading to the proliferation of TM4 cells., Conclusions: Prenatal exposure to DBP led to abnormal proliferation of SCs in prepubertal mice by affecting ubiquitination of the key proliferation-related protein IRAK1 via downregulation of Peli2.

Di-butyl phthalate (DBP) is commonly added to make plastics softer and more pliable and is found in a variety of consumer and industrial products. Alarmingly high levels of DBP have been detected in water and sediment as DBP leaches from products. These levels are concerning and have led the Environmental Protection Agency to label DBP as a priority environmental pollutant and the European Commission to label DBP as a priority substance. Given the ubiquitous presence of DBP globally and continuous exposure to DBP, studies on the developmental toxicity of DBP are needed. The endocrine disrupting effects of DBP are well documented, but developmental toxicity of DBP during critical developmental time windows is understudied. Here, we investigate the developmental effects of DBP exposure during early development. We find defects in craniofacial development including a decrease in overall cranial size in DBP treated embryos, but the intraocular distance was increased compared to controls. Further investigation of jawbone development demonstrated loss of and disorganization of cartilage development. Defects in vascular innervation and neuronal patterning were also noted. Here we conclude that exposure to DBP during crucial time windows of embryonic development is toxic to craniofacial development.

In this study, the effects of di-n-butyl phthalate (DBP) on the phyllosphere bacterial community of field mustard (Brassica campestris L.) at the five-leaf stage were investigated. The indigenous alpha-diversity of the phyllosphere bacteria was altered after spraying with different concentrations of DBP. Shannon diversity indices were significantly changed on day 5 after treatment at DBP concentrations > 400 mg L -1 (P > 0.05). Nevertheless, the difference between treatment and control was not significant on day 9 after DBP treatment (P > 0.05). Exposure to DBP resulted in a decrease in Proteobacteria and Firmicutes, and an increase in Actinobacteria at all sampling intervals. These changes included significant increases in the relative abundance of Paracoccus and Rhodococcus, and significant decreases in that of Pseudomonas, Exiguobacterium, an unclassified genus of Pseudomonadaceae, and an unclassified genus of Enterobacteriaceae. This study provides new evidence for the possibility of using phyllosphere microbiota to remediate DBP contamination.

Background: Dibutyl phthalate (DBP) is an endocrine disruptor and used in some medication coatings, such as mesalamine for treatment inflammatory bowel disease (IBD)., Objectives: To determine whether high-DBP from some mesalamine medications alters thyroid function., Methods: Seventy men with IBD, without thyroid disease or any radiation history participated in a crossover-crossback prospective study and provided up to 6 serum samples (2:baseline, 2:crossover, 2:crossback). Men on non-DBP mesalamine (background exposure) at baseline crossed-over to DBP-mesalamine (high exposure) then crossed-back to non-DBP mesalamine (B 1 HB 2 -arm) and vice versa for men on DBP-mesalamine at baseline (H 1 BH 2 -arm). Serum concentrations of total triiodothyronine (T3), total thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb)., Results: After crossover in B 1 HB 2 -arm (26 men, 134 samples), T3 decreased 10% (95% confidence interval (CI): 14%,-5%), T3/T4 ratio decreased 8% (CI: 12%,-3%), TPOAb, and TgAb concentrations decreased, 11% (-20%, -2%) and 15% (-23%, -5%), respectively; after crossback, they increased. When men in the H 1 BH 2 -arm (44 men, 193 samples) crossed-over, T3 decreased 7% (CI: -11%, -2%) and T3/T4 ratio decreased 6% (CI: -9%, -2%). After crossback, only TgAb increased and FT4 decreased., Conclusions: High-DBP novel exposure or removal from chronic high-DBP exposure could alter elements of the thyroid system, and most probably alters the peripheral T4 conversion to T3 and thyroid autoimmunity, consistent with thyroid disruption. After exposure removal, these trends were mostly reversed., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Phthalates have been extensively used as plasticizers in various fields, including food, cosmetic, and pharmaceutical industry. Those compounds do not form covalent bonds to substances they are being added to, and thus they may migrate easily and penetrate various products used every day. They may reach organisms with air, food, or by a direct skin contact. Significant levels of phthalates and their metabolites are found in urine, breast milk, blood serum, venous blood, and cord blood. The purpose of this study was to assess the simple toxicity (haemolysis) and programmed death (eryptosis) caused by following phthalates: di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP) and their metabolites: mono-n-butyl phthalate (MBP) and mono-benzyl phthalate (MBzP) in vitro in human RBCs. RBCs were incubated with the above mentioned compounds at concentrations ranging between 0.5 and 500 μg/mL for 24 h. Obtained results demonstrated that DBP and BBP possess higher haemolytic properties compared to their metabolites. The lethal concentration (LC 50 ) was determined. The value was 126.37 ± 5.94 μg/mL for DBP, and 103.65 ± 4.03 μg/mL for BBP, and for metabolites the LC 50 value was over 500 μg/mL. All compounds induced eryptosis causing translocation of phosphatidylserine, increased cytosolic calcium ions level, increased caspase-3 and calpain activation in human erythrocytes. BBP caused translocation of phosphatidylserine at a lower concentration compared to DBP. In case of other parameters, more pronounced changes were evoked by DBP at lower concentrations. Metabolites showed a significantly lower toxicity compared to parent compounds., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Phthalates, such as dibutyl phthalate (DBP), are endocrine disruptors used in some medication coatings e.g., mesalamine to treat inflammatory bowel disease (IBD)., Objectives: Taking advantage of different mesalamine formulations with/without DBP, we assessed whether DBP from mesalamine (>1000x background) altered serum hormones., Methods: Men (N=73) with IBD participated in a crossover-crossback prospective study and provided up to 6 serum samples (2:baseline, 2:crossover, 2:crossback). Men on non-DBP mesalamine (background) at baseline crossed-over for 4 months to DBP-mesalamine (high) and then crossed-back for 4 months to non-DBP mesalamine (B 1 HB 2 -arm) and vice versa for men on DBP-mesalamine at baseline (H 1 BH 2 -arm). We divided H 1 BH 2 -arm at the median (H 1 <3yrs or H 1 ≥3yrs). We estimated crossover and crossback % changes in serum reproductive hormones using multivariable linear mixed effect models., Results: When B 1 HB 2 -arm (26 men,134 samples) crossed-over, luteinizing hormone decreased 13.9% (95% confidence interval(CI): -23.6,-3.0) and testosterone, inhibin-B, and follicle-stimulating hormone (FSH) marginally decreased; after crossback all increased 8-14%. H 1 BH 2 -arm, H 1 ≥3yrs (25 men,107samples) had no changes at crossover or crossback whereas in H 1 BH 2 -arm,H 1 <3yrs (22 men,100 samples) after crossover, inhibin-B increased 13.2% (CI: 4.2,22.9), FSH decreased 9.9% (CI: -17.9,-1.1) and after crossback, inhibin-B further increased 11.3%, and FSH marginally increased., Conclusions: High-DBP exposure may disrupt pituitary-gonadal hormones that largely reversed after exposure removal, but only in men with no or short previous high-exposure history. Paradoxically, men with longer duration of high-DBP exposure, exposure removal did not change hormone levels, suggesting that long-term high-DBP exposure may alter the pituitary-gonadal axis and make it insensitive to exposure changes., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Chronic lymphocytic thyroiditis (CLT) is a common autoimmune disorder. The possible pathogenic role and mechanism of dibutyl phthalate (DBP) in CLT is still controversial. Experiments were conducted after 35-days of oral exposure to the three concentrations of DBP or saline, and three immunizations with thyroglobulin (TG). Healthy female Wistar rats were randomly divided into ten exposure groups (n = 8 each): (A) saline control, (B) 0.5 mg/kg/d DBP, (C) 5 mg/kg/d DBP, (D) 50 mg/kg/d DBP, (E) TG-immunized group, (F) TG- combined with 0.5 mg/kg/d DBP, (G) TG- combined with 5 mg/kg/d DBP, (H) TG- combined with 50 mg/kg/d DBP, (I) TG- combined with 50 mg/kg/d DBP plus 100 mg/kg/d vitamin C; (J) 100 mg/kg/d vitamin C. We showed that oral exposure DBP can aggravate CLT in rats. This deterioration was concomitant with increased thyroid auto antibodies, Th1/Th2 imbalance and Th17 immune response, activated pro-inflammatory and apoptosis pathways, and increased thyroid dysfunction in rats. Our results also suggested that DBP could promote oxidative damage. The study also found that vitamin C reduced the levels of oxidative stress and alleviated CLT. In short, the study showed that DBP exacerbated CLT through oxidative stress.

Dibutyl phthalate is an important phthalate ester extensively used in various products like plastics, adhesives, inks, pharmaceuticals, lacquers, varnishes, paper coatings, safety glasses, and cosmetics. The exposure of DBP to "one's health" is therefore inevitable. The present study focuses on elucidating the effect of low doses of DBP on anthropometric parameters and markers of obesity in rats in a 13-week study. A total of 48 rats were divided into three treatment groups as mg DBP/kg body weight per day: (a) 0 mg/kg (control), (b) 10 mg/kg (DBP-10), and (c) 50 mg/kg (DBP-50). The rats in each treatment (n = 16) were further equally divided into male and female rats for studying treatment and gender interaction. Anthropometric parameters, nutritional determinants, and markers of obesity in rats were studied. Two-way ANOVA was used to analyze the data (p < 0.05). Tukey's post hoc test was used for pairwise comparisons. DBP increased body weight gain, feed efficiency, abdominal to thoracic circumference ratio, and body mass index in rats. Serum cholesterol and alkaline phosphatase concentrations decreased with DBP treatment. Serum albumin, glucose, creatinine, and alanine transaminase increased with DBP treatments. Serum lactate dehydrogenase increased in DBP-10 but was not affected by DBP-50. Further low-dose investigations are needed to assess non-monotonic dose responses.

This study was to determine the impact of maternal exposure to di-n-butyl phthalate (DBP) on renal development and fibrosis in adult offspring. Pregnant rats received DBP at a dose of 850 mg/kg BW/day by oral perfusion during gestational days 14-18. In DBP exposed newborn offspring, gross observation and histopathological examination revealed the dysplasia of kidney. The expression of genes related to renal development was also changed. In DBP exposed adult offspring, histopathological examination and Masson's trichrome staining revealed the pathological changes of renal fibrosis. Furthermore, higher expression levels of transforming growth factor- β (TGF-β) and alpha-smooth muscle actin (α-SMA) were also detected. In vitro studies reveal that DBP promoted the activation of NRK49F cells and G2/M arrest in NRK52E cells at a sublethal dose. The effect of DBP on these cell lines was linked to the generation of oxidative stress. In addition, DBP induced oxidative stress in both renal fibroblasts and tubular epithelial cells, whereas vitamin C ameliorated the changes caused by DBP. In conclusion, our results showed that prenatal exposure to DBP may generate oxidative stress in both renal fibroblasts and tubular epithelial cells, leading to kidney dysplasia and renal fibrosis.

Background: Phthalates are widely used chemicals with ubiquitous exposure. Dibutyl-phthalate (DBP), a male reproductive toxicant in animals, is understudied in humans. Some mesalamine medications used to treat inflammatory bowel disease (IBD) have DBP in their coating, whereas other mesalamine formulations do not., Objectives: Taking advantage of differences in mesalamine formulations, we investigated whether high-DBP exposure from mesalamine medications was associated with decreased semen parameters., Methods: 73 men with IBD taking mesalamine participated in a crossover-crossback prospective study. Men taking non-DBP containing mesalamine at baseline i.e., background exposure, crossed-over for four months to high-DBP mesalamine and then crossed-back for four months to their non-DBP mesalamine (B1HB2-arm;Background1-High-Background2) and vice versa for men taking high-DBP mesalamine at baseline (H1BH2-arm;High1-Background-High2). Men provided up to six semen samples (2: baseline, 2: crossover and 2: crossback)., Results: We estimated crossover, crossback and carryover effects using linear mixed models adjusted for abstinence time, age, season and duration on high-DBP mesalamine at baseline. Semen parameters in B1HB2-arm (26 men, 133 samples) decreased after high-DBP mesalamine exposure (crossover versus baseline), especially motility parameters, and continued to decrease further even after crossback to non-DBP mesalamine (crossback versus crossover). The cumulative carryover effect of high-DBP (crossback versus baseline) was a decrease of % total sperm motility by 7.61(CI:-13.1, -2.15), % progressive sperm motility by 4.23(CI:-8.05, -0.4) and motile sperm count by 26.0% (CI:-46.2%, 1.7%). However, H1BH2-arm (47 men, 199 samples) had no significant change during crossover or crossback., Conclusions: Men newly exposed to high-DBP mesalamine for four months had a cumulative reduction in several semen parameters, primarily sperm motility, that was more pronounced and statistically significant even after exposure ended for four months., Competing Interests: Potential Conflict of interest: Joshua Korzenik, research support from Abbvie, Transparency Life Sciences and Takeda, consulting with Abbvie, a founder of a company called ColonaryConcepts; Alan C. Moss, prior research grants from Shire, Salix and Aptalis, manufacturers of mesalamine medications., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Dibutyl phthalate (DBP) is a widely used synthetic phthalic diester and monobutyl phthalate (MBP) is its main metabolite. DBP can be released into the environment and potentially disrupting mammalian male reproductive endocrine system. However, the potencies of DBP and MBP to inhibit Leydig cell steroidogenesis and their possible mechanisms are not clear. Immature Leydig cells isolated from rats were cultured with 0.05-50 μM DBP or MBP for 3 h in combination with testosterone synthesis regulator or intermediate. The concentrations of 5α-androstanediol and testosterone in the media were measured, and the mRNA levels of the androgen biosynthetic genes were detected by qPCR. The direct actions of DBP or MBP on CYP11A1, CYP17A1, SRD5A1, and AKR1C14 activities were measured. MBP inhibited androgen production by the immature Leydig cell at as low as 50 nM, while 50 μM was required for DBP to suppress its androgen production. MBP mainly downregulated Cyp11a1 and Hsd3b1 expression levels at 50 nM. However, 50 μM DBP downregulated Star, Hsd3b1, and Hsd17b3 expression levels and directly inhibited CYP11A1 and CYP17A1 activities. In conclusion, DBP is metabolized to more potent inhibitor MBP that downregulated the expression levels of some androgen biosynthetic enzymes.

Objective: To investigate the impact of in utero exposure to di-n-butyl phthalate (DBP) on the apoptosis of testicular cells in the pubertal male rat offspring., Methods: Ten pregnant SD rats were randomly divided into a control and an experimental group to be treated intragastrically with olive oil (1 ml per day) and DBP (500 mg per kg of body weight per day) respectively between gestation days 12 and 19. At the pubertal age (postnatal day 45, PND 45), the testes of the male rat offspring were removed for observation of the cell structure under the transmission electron microscope and the development of different spermatogenetic cells by HE staining. The apoptosis of testicular cells was detected by the TUNEL method, the expressions of the apoptosis-regulating proteins Bcl-2, Bcl-XL, Bax and p53 were determined by immunohistochemistry and Western blot, and the data obtained were compared between the two groups by t-test., Results: Transmission electron microscopy revealed increased apoptosis and vacuolization of testicular cells in the PND-45 rat offspring, HE staining showed markedly decreased numbers of different spermatogenetic cells, TUNEL manifested significantly increased apoptosis of testicular cells in the experimental group as compared with the control (12.00 ± 5. 22 vs 3.17 ± 1.47, P < 0.01), and immunohistochemistry and Western blot exhibited remarkably higher expressions of Bax and p53 in the former than in the latter group (P < 0.05)., Conclusion: In utero exposure to DBP can increase the apoptosis of germ cells and Sertoli cells, induce the vacuolization of testicular cells, and significantly elevate the expressions of the apoptosis-promoting proteins Bax and p53 in the pubertal male rat offspring.

Phthalates and bisphenol A (BPA) are ubiquitous contaminants identified as endocrine disruptors. Phthalates are worldwide used as plasticizers, in particular to improve the mechanical properties of polymers such as polyvinyl chloride. Because they are not chemically bound to the polymer, they tend to leach out with time and use. Di-2-ethylhexyl phthalate (DEHP) and di-n-butyl phthalate (DnBP) are the two most common phthalates. BPA is an estrogenic compound used to manufacture polycarbonate containers for food and drink, including baby bottles. It can migrate from container into foods, especially at elevated temperatures. Diet is a predominant source of exposure for phthalates and BPA, especially for infants. The aim of this study was to test the presence of DEHP, DnBP, and BPA in infant formulas. DEHP, DnBP, and BPA concentrations were measured in 22 liquid and 28 powder milks by gas chromatography with flame ionization detection and high performance liquid chromatography with fluorimetric detection, respectively. DEHP concentrations in our samples were between 0.005 and 5.088 μg/g (median 0.906 μg/g), DnBP concentrations were between 0.008 and 1.297 μg/g (median 0.053 μg/g), and BPA concentrations were between 0.003 and 0.375 μg/g (median 0.015 μg/g). Concentrations of the investigated contaminants in liquid and powder milks were not significantly different, even though samples were packed in different types of containers. These data point out potential hazards for infants fed with baby formulas. Contamination seems more related to the production of formulas than to a release from containers.

Di-n-Butyl (DBP) and Di-(2-EthylHexyl) (DEHP) phthalates can leach from daily-use products resulting in environmental exposure. In male rodents, phthalate exposure results in reproductive effects. To evaluate effects on the immature primate testis, testis fragments from 6-month-old rhesus macaques were grafted subcutaneously to immune-deficient mice, which were exposed to 0, 10, or 500 mg/kg of DBP or DEHP for 14 weeks or 28 weeks (DBP only). DBP exposure reduced the expression of key steroidogenic genes, indicating that Leydig cell function was compromised. Exposure to 500 mg/kg impaired tubule formation and germ cell differentiation and reduced numbers of spermatogonia. Exposure to 10 mg/kg did not affect development, but reduced Sertoli cell number and resulted in increased expression of inhibin B. Exposure to DEHP for 14 week also affected steroidogenic genes expression. Therefore, long-term exposure to phthalate esters affected development and function of the primate testis in a time and dosage dependent manner., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

It is well known that the endocrine-disrupting chemical (EDC) dibutylphthalate (DBP) inhibits testosterone synthesis and can lead to feminisation in male laboratory animals. Moreover, it has long been speculated that human exposure would result in the similar effects, but this is difficult to study because specific human exposure cohorts are rare. We report increases in the incidences of hypospadias (p<0.05), cryptorchidism (p<0.05) and breast cancer (p<0.05) in the children of New Zealand soldiers who served in Malaya (1948-1960) and were exposed to DBP applied daily to their clothing as an acaricide to prevent tick-transmitted bush typhus. In addition, we modelled absorption of DBP from the soldiers' clothing and using published data for skin absorption, and calculated a large theoretical absorbed dose of 64 mg/kg body weight/day which is similar to DBP's lowest observed adverse effect level (LOAEL) of 50 mg/kg body weight/day and thus indicates a biological effect is possible. This is the first report of a multigenerational developmental effect following DBP exposure in human males.

Background: Tattooing has recently become increasingly popular. Using tiny needles, tattooists place the tattoo ink in the dermis along with numerous unknown ingredients. Most tattoos consist of black inks, which are predominantly composed of soot products (carbon black with polycyclic aromatic hydrocarbons)., Objectives: Black tattoos cause skin problems, including allergic reactions, but the responsible substance frequently remains unknown., Material/methods: We applied gas chromatograph-mass spectrometry analysis to search for hazardous compounds in 14 different commercially available black tattoo ink samples., Results: The analysis revealed that all inks contained the softener substance dibutyl phthalate (0.12-691.2 µg/g). Some of the inks contained hexachloro-1,3-butadiene (0.08-4.52 µg/g), metheneamine (0.08-21.64 µg/g), dibenzofuran (0.02-1.62 µg/g), benzophenone (0.26-556.66 µg/g), and 9-fluorenone (0.04-3.04 µg/g)., Conclusion: The sensitizing agent dibutyl phthalate acts directly on keratinocytes and can drive Th2 responses following skin exposure via induction of thymic stromal lymphopoietin gene expression. Hexachloro-1,3-butadiene is genotoxic in vitro and 9-fluorenone is cytotoxic, generating reactive oxygen species under light exposure. The substances found in the inks might be partially responsible for adverse skin reactions to tattoos., (© 2011 John Wiley & Sons A/S.)

Phthalates like di-n-butyl phthalate (DnBP) and diisobutyl phthalate (DiBP) are commonly used as plasticisers, enteric coatings in medications and their metabolites (MnBP respectively MiBP) are suspect of adverse endocrine activities. The aim of this study was to determine kinetical data in humans after the application of a drug containing 3600 microg of DnBP and to quantify main metabolites of DnBP and DiBP with and without glucuronidase treatment. Since commonly glucuronides do not exhibit endocrine activity it is of interest to determine the potentially active metabolite like free MnBP and MiBP for a valid risk assessment. After the application of one capsule containing 3600 microg of DnBP to 17 volunteers 78% (median of 2248 microg of total MnBP) of administered DnBP was found within 24h in urine. After 24h the levels of MnBP in urine were comparable to concentrations before administration showing a fast elimination. In contrast to controls in all urine samples collected within 24h after the administration of the drug free MnBP was observed with a median of 4% of total MnBP. In controls total MnBP and MiBP were found in median concentration of 23 microg/24h and about 50 microg/24h, respectively and therefore environmental exposure to DnBP is only 1% compared to medication. Since an uptake of 3600 microg in only one capsule is already above the tolerable daily intake (TDI) for DnBP of 10 microg/kg b.w. from a preventive health protection DnBP should be replaced in medical drugs.

Phthalate esters were reported to damage fetal and postnatal testes of experimental animals, but the molecular mechanisms underlying these effects remain unknown. The time-response effects of di(n-butyl) phthalate (DBP) on the expression patterns of the testicular genes in male Sprague-Dawley rats were examined for different periods of exposure (1, 7, 14, or 28 d). The steroidogenic- or spermatogenic-related gene expression patterns were measured using reverse-transcription polymerase chain reaction (RT-PCR). After 28 d of exposure, the serum concentrations of DBP and monobutyl phthalate (MBP) increased in a dose-dependent manner, and were significantly higher in the DBP-treated rats than in the control rats. Liver weight was increased markedly at 28 d after DBP exposure at 750 mg/kg/d. Testicular weight was reduced significantly after 14 and 28 d of exposure. DBP (750 mg/kg/d) produced a significant increase in scavenger receptor class B1 (SR-B1) and steroidogenic acute regulatory (StAR) mRNA after 14 and 28 d of exposure. The level of cytochrome P-450 (P450) side-chain cleavage (P450scc) mRNA decreased in the group treated with DBP at 750 mg/kg/d at 7 d. After 14 and 28 d of exposure, there was an apparent increase in P450scc mRNA. High doses of DBP significantly increased the Cyp17 mRNA level after 28 d of exposure. At 7 d, a significant decrease in Cyp19 mRNA was observed only in the group exposed to 750 mg/kg/d DBP. In addition, DBP significantly decreased the levels of a spermatid-specific gene (Spag4) and lactate dehydrogenase A (LDHA) mRNA after 7 d of exposure. The levels of androgen receptor (AR), estrogen receptor-alpha (ER-alpha), and retinoid X receptor-gamma (RXR-r) expression decreased significantly in a time- or dose-dependent manner. DBP significantly increased the peroxisome proliferator-activated receptor-gamma (PPAR-r) and phosphorylated extracellular-signal-regulated kinase (p-ERK1/2) levels in the testis. These results suggest that the acute and chronic effects of DBP on the steroidogenic pathways in the testes show mechanistically distinct patterns. Data thus provide some insights into the molecular mechanisms underlying DBP-induced testicular dysgenesis.

Estrogenic activity of phthalate esters in dental soft resins was evaluated with an amphibian system consisting of a vitellogenin (VTG)-detecting Enzyme-Linked Immunosorbent Assay and a primary-cultured hepatocyte assay using adult male Xenopus laevis. In particular, phthalate esters--Di-n-butyl phthalate (DBP), Butyl phthalyl butyl glycolate (BPBG), Benzyl butyl phthalate (BBP), and Benzyl benzoate (BB)--were investigated. Bisphenol A (BPA) was prepared for comparison with these chemicals, and 17beta-estradiol (E2) was used as a positive control. The chemicals were diluted in dimethyl sulfoxide (DMSO) to obtain final concentrations ranging from 10(-11) to 10(-4) mol/l. BPA induced estrogenic activity at a concentration of 1.1x10(-6) mol/l, while E2 showed at 4.1x10(-11) mol/l. DBP, BBP, BB, and BPBG showed no estrogenic activity at concentrations between 4x10(-7) mol/l and 1x10(-4) mol/l. The latter result indicated that these phthalate esters might be metabolically transformed into non-estrogenic substances in Xenopus hepatocytes. Furthermore, this study demonstrated that through in vitro metabolism assessment, the estrogenic activity of chemical substances could be directly detected in terms of VTG secretion in primary-cultured Xenopus hepatocytes.

The phthalate ester di(n-butyl) phthalate (DBP) causes feminization of male rats upon in utero exposure by repressing expression of genes required for testicular steroidogenesis. Previous work in our laboratory has shown that repression of gene expression and steroidogenesis in the fetal testis is apparent within a few hours of DBP exposure. The purpose of this study was to determine the precise timing of DBP-associated gene expression changes in the fetal testis using transcriptional profiling and to determine whether DBP exerts similar effects on steroidogenesis in the fetal adrenal. A DBP time-course experiment showed that testicular steroidogenesis was decreased within 1 h of DBP exposure and that this decrease preceded the repressed transcription of Star (steroidogenic acute regulatory protein); Scarb1 (scavenger receptor class B, member 1; also know as Sr-b1); Cyp11a1 (cytochrome P450, family 11, subfamily a, polypeptide 1; also known as P450SCC); and Cyp17a1 (cytochrome P450 family 17, subfamily a, polypeptide 1; also known as Cyp17). Gene expression profiling demonstrated rapid (within 1 to 3 h) and transient induction of immediate early genes in the fetal testis after administration of DBP to the pregnant dam. There was a statistically insignificant decrease in corticosterone production by the fetal adrenal after in utero exposure to DBP from Gestation Day 12 to Gestation Day 19. The extent of steroidogenesis diminution was much less in the adrenal than in the testis (approximately 45% decrease in the adrenal versus 87% decrease in the testis) and expression of genes required for steroidogenesis in the adrenal was unaffected by DBP. Together, these studies demonstrate that DBP initiates a rapid and dynamic change in gene expression in the fetal testis that likely plays a role in the reduction in steroidogenesis that is unique to the fetal testis relative to the steroidogenically active fetal adrenal.

The modulation of common carp, Cyprinus carpio L. phagocytic cells by Di-n-butyl phthalate (DBP) and Di-2-ethylhexyl phthalate (DEHP) were analyzed in vitro. Carp head kidney leucocytes were cultured in a RPMI 1640 medium containing DBP or DEHP at concentration of 1-1000 nM and the production of superoxide anion was measured via the in vitro reduction of nitroblue tetrazolium (NBT). Macrophages incubated with 100 up to 1000 nM of DBP showed an increase in their production of superoxide anion in comparison with the control macrophages which, were cultured without DBP. DEHP also increased the production of superoxide anion in phagocytic cells from carp kidneys. Phagocytic cells treated with 10 and 100 ng of DEHP showed increased phagocytic activity. DBP and DEHP also significantly increased the production of nitric oxide in carp macrophages. These results showed that DBP and DEHP modulate the function of phagocytic cells in vitro.

Environmental chemicals may modulate the endocrine system through interaction with plasma sex steroid-binding proteins (SBP) and SBP-regulated processes. Some of these chemicals, which are known to interact with the estrogen receptor (ER), were found to bind competitively to the Atlantic salmon (Salmo salar) SBP and potentially disrupt the endocrine function of these proteins. Furthermore, both weakly acting (di-n-butyl phthalate) and potent estrogen mimics (ethynylestradiol), were able to induce a substantial up-regulation of circulating levels of SBP in vivo. Interestingly, modulation of SBP-levels was found to be a more sensitive endpoint than chemically induced interference with classical ER-mediated mechanisms for weakly acting estrogen mimics like di-(n-butyl) phthalate. Interference with the endocrine function of SBPs may thus introduce a novel mechanism for endocrine disruption. and give additional answers to the question why some weakly acting xenoestrogens are causing "estrogen-like" reproductive disturbances in developing males.

This present study was undertaken to examine the effects of DBP and its metabolite mono-n-butyl phthalate (MBuP) on cytotoxicity and differentiation in cultured rat embryonic limb bud cells. When limb bud cells extracted from rats on gestation d 12.5 were treated with DBP or MBuP for 96 h, induction of cytotoxicity and inhibition of cell differentiation were observed in a concentration-dependent manner. However, MBuP elicited a toxic effect at higher concentrations than DBP. The IC50 values of DBP for cytotoxicity (measured by neutral red uptake) and cell differentiation (measured by alcian blue staining) were 25.54 microg/ml (91.75 microM) and 21.21 microg/ml (76.20 microM), respectively. The IC50 values of MBuP for cytotoxicity and cell differentiation were 307.24 microg/ml (1.38 mM) and 142.61 microg/ml (0.64 mM), respectively. in order to determine whether free radicals are related to induction of cytotoxicity and inhibition of differentiation by DBP in limb bud cells, DBP was coadministered with several antioxidants, including catalase and vitamin E acetate to limb bud cells. Cotreatment with catalase and vitamin E acetate decreased induction of cytotoxicity and inhibition of differentiation by DBP in limb bud cells. However, these compounds did not show any protective effect against MBuP. Results indicate that DBP and MBuP induced developmental toxicity in rat embryonic limb bud cells and suggest that this effect of DBP might be exerted through oxidative stress.

To examine the effects of dibutyl phthalate (DBP) on gonadal sex differentiation, genetically male tadpoles of Rana rugosa were exposed to dilute solutions of DBP at concentrations of 0.1, 1, or 10 microM during days 19-23 after fertilization, which is the critical period of gonadal sex differentiation in R. rugosa. Tadpoles were necropsied on day 40. The genetically male tadpoles were produced from crossings between males (ZZ) of one local population, in which females are the heterogametic sex, and females (XX) of another local population, in which males are the heterogametic sex. As positive control groups, tadpoles were exposed to dilute solutions of 17beta-estradiol (E(2)) at concentrations of 0. 01, 0.1, or 1 microM during the same period. The internal structure of the gonads was histologically examined in a total of 30 control tadpoles, 86 E(2)-treated tadpoles, and 90 DBP-treated tadpoles. The gonads of the control tadpoles all showed the typical structure of testes. In contrast, 0.01, 0.1, and 1 microM E(2) treatments caused the undifferentiated gonads of 18, 63, and 100% of the tadpoles, respectively, to develop into gonads of complete or partial ovarian structure. After 0.1, 1, and 10 microM DBP treatment, 0, 7, and 17% of tadpoles, respectively, were similarly affected. These findings suggest that DBP was about 1,000-fold less potent than E(2). Nevertheless, DBP is an environmentally dangerous hormone that disrupts the pathways of testicular differentiation in genetically male animals.

The complexity of carcinogenesis in squamous cell cancer (SCC) of the upper aerodigestive tract requires examining environmental risk factors, including mutagen sensitivities to xenobiotics. Three environmental, occupational, and habitual pollutants - dibutylphthalate (DBP), diisobutylphthalate (DiBP), and N'nitrosodiethylamine (NDELA) - were submitted to genotoxicity testing on mucosal biopsy specimens of tumor and nontumor patients in vitro. The single-cell microgel electrophoresis (Comet) assay was applied to detect DNA strand breaks in human epithelial cells of the pharynx and larynx from nontumor patients, patients with SCC of the oropharynx and patients with SCC of the larynx. Genotoxicity was found for DBP, DiBP, and NDELA in cells derived from nontumor and tumor patients. With respect to phthalates, Olive tail moment (OTM) levels were higher in patients with SCC of the oropharynx and SCC of the larynx (P < 0.01), the latter showing even more pronounced genotoxicity for DiBP. Testing epithelial cells of the patients with either oropharyngeal or laryngeal SCC for NDELA demonstrated results similar to the nontumor patients. Present findings indicate heterogeneous mutagen sensitivities to some but not all xenobiotics.

We report on a patient who was taking a Gelomyrtol forte capsule, a mucosecretolytic herbal product, to treat an infection of the upper respiratory tract. Itching, urticaria and respiratory distress occurred after 20 min which culminated in anaphylactic shock. Prick tests were carried out with the individual substances from Gelomyrtol forte capsules. Dibutyl phthalate produced a strong positive result. It is used as a plasticizer in films covering tablets, dragées and capsules. As a triggering agent of anaphylactic reactions to drugs, the auxiliary materials, e.g. dibutyl phthalate, should also be taken into consideration.