Narcotics information management system in South Korea: system development and innovation.

BACKGROUND: As the misuse and abuse of medical narcotics are increasing in South Korea, an information system for the integrated information management of medical narcotic drugs across the nation is needed. This paper presents the development process of the Narcotics Information Management System (NIMS) for the monitoring of medical narcotics usage and the results of its implementation. METHODS: As the NIMS enforces that all narcotics handlers digitally report all information on handling medical narcotic drugs, the functional requirements of the NIMS have been identified in accordance with the Narcotics Control Act. In addition to the functional requirements, the non-functional requirements of the NIMS have been elicited by major narcotics handlers and their associations. The non-functional requirements include privacy, availability, connectivity, interoperability, and data integrity. The system design with entity-relationship diagrams and its implementation processes have been presented. RESULTS: The NIMS encompasses all narcotic handlers, which comprise exporting, importing, and pharmaceutical companies; wholesalers; hospitals and clinics; and pharmacies, collecting over 120 million cases annually. It enables transparent monitoring throughout the life cycle, from manufacturing, sales, purchase, and disposal of narcotics. As a result, the number of prescriptions for medical narcotics has been reduced by 9.2%. CONCLUSIONS: To the best of our knowledge, the NIMS is the world's first system to manage all information on the total life cycle of medical narcotics, including imports, production, distribution, use, and disposal of drugs. This system has enabled the safety management and monitoring of medical narcotic drugs. Additionally, it provides consistent and transparent information to physicians and patients, leading to the autonomous safety management of narcotics. The successful development of the NIMS can provide guidelines for implementing a narcotics management system in other countries.

Risk of aortic aneurysm and aortic dissection with the use of fluoroquinolones in Korea: a nested case-control study.

BACKGROUND: Recent studies have raised concern about the association of fluoroquinolones with an increased risk of aortic aneurysm and aortic dissection. We aimed to evaluate such risk in a Korean population. METHODS: We conducted a nested case-control study using data from the National Health Insurance Service collected from 2013 to 2017 in Korea. The study cohort included patients older than 40 years and excluded patients who had used fluoroquinolones or been diagnosed with aortic aneurysm, aortic dissection, or related diseases 1 year prior to the cohort entry date. We randomly matched four controls in the risk set with each case of aortic aneurysm and aortic dissection (same sex, age, and cohort entry date). We assessed the risk of aortic aneurysm and aortic dissection from fluoroquinolones and adjusted for potential confounders using a conditional logistic regression model. RESULTS: A total of 29,638 aortic aneurysm and aortic dissection patients were identified between 2014 and 2017. The use of fluoroquinolones within a year was associated with a 10% increased risk of aortic aneurysm and aortic dissection (adjusted odds ratio: 1.10, 95% CI 1.07-1.14, p < 0.05) compared with nonusers. The risk was higher in patients who had used fluoroquinolones within 60 days (adjusted odds ratio: 1.53, 95% CI 1.46-1.62, p < 0.05). The risk of aortic aneurysm and aortic dissection positively correlated with the cumulative dose and duration of fluoroquinolone therapy (p < 0.001). CONCLUSIONS: Our study provides real-world evidence of the risk of aortic aneurysm and aortic dissection from fluoroquinolones in Korea. Patients and medical professionals should be aware that fluoroquinolones can increase the risk of aortic aneurysm and aortic dissection, which may be acerbated by high dosage and duration of use.

Screening of dihydropyrimidine dehydrogenase genetic variants by direct sequencing in different ethnic groups.

Dihydropyrimidine dehydrogenase (DPYD) is an enzyme that regulates the rate-limiting step in pyrimidine metabolism, especially catabolism of fluorouracil, a chemotherapeutic agent for cancer. In order to determine the genetic distribution of DPYD, we directly sequenced 288 subjects from five ethnic groups (96 Koreans, 48 Japanese, 48 Han Chinese, 48 African Americans, and 48 European Americans). As a result, 56 polymorphisms were observed, including 6 core polymorphisms and 18 novel polymorphisms. Allele frequencies were nearly the same across the Asian populations, Korean, Han Chinese and Japanese, whereas several SNPs showed different genetic distributions between Asians and other ethnic populations (African American and European American). Additional in silico analysis was performed to predict the function of novel SNPs. One nonsynonymous SNP (+199381A > G, Asn151Asp) was predicted to change its polarity of amino acid (Asn, neutral to Asp, negative). These findings would be valuable for further research, including pharmacogenetic and drug responses studies.

Screening of Genetic Polymorphisms of CYP3A4 and CYP3A5 Genes.

Given the CYP3A4 and CYP3A5's impact on the efficacy of drugs, the genetic backgrounds of individuals and populations are regarded as an important factor to be considered in the prescription of personalized medicine. However, genetic studies with Korean population are relatively scarce compared to those with other populations. In this study, we aimed to identify CYP3A4/5 polymorphisms and compare the genotype distributions among five ethnicities. To identify CYP3A4/5 SNPs, we first performed direct sequencing with 288 DNA samples which consisted of 96 Koreans, 48 European-Americans, 48 African-Americans, 48 Han Chinese, and 48 Japanese. The direct sequencing identified 15 novel SNPs, as well as 42 known polymorphisms. We defined the genotype distributions, and compared the allele frequencies among five ethnicities. The results showed that minor allele frequencies of Korean population were similar with those of the Japanese and Han Chinese populations, whereas there were distinct differences from European-Americans or African-Americans. Among the pharmacogenetic markers, frequencies of CYP3A4*1B (rs2740574) and CYP3A5*3C (rs776742) in Asian groups were different from those in other populations. In addition, minor allele frequency of CYP3A4*18 (rs28371759) was the highest in Korean population. Additional in silico analysis predicted that two novel non-synonymous SNPs in CYP3A5 (+27256C>T, P389S and +31546T>G, I488S) could alter protein structure. The frequency distributions of the identified polymorphisms in the present study may contribute to the expansion of pharmacogenetic knowledge.

Risk of genital and urinary tract infections associated with SGLT-2 inhibitors as an add-on therapy to metformin in patients with type 2 diabetes mellitus: A retrospective cohort study in Korea.

Sodium-glucose cotransporter-2 (SGLT-2) inhibitors are antidiabetic drugs with associated safety concerns regarding the risk of genital and urinary tract infections. This study assessed the risk of genital and urinary tract infections associated with prescription of SGLT-2 inhibitors as an add-on therapy to metformin in patients with type 2 diabetes mellitus (T2DM) compared to dipeptidyl peptidase-4 (DPP-4) inhibitors, sulfonylurea (SU), and thiazolidinedione (TZD). We conducted a retrospective cohort study using the NHIS-National Health Insurance-Database in Korea from 2014 to 2017. Patients aged ≥19 years and those diagnosed with T2DM prior to drug prescription were enrolled. The outcomes were genital and urinary tract infections. Analysis was performed using Cox's proportional hazard model following 1:1 propensity score matching to calculate the hazard ratio (HR) with a 95% confidence interval (CI). Among the 107 131 patients included in the study, a total of 7738, 7145, and 2175 patients were assigned to the DPP-4 inhibitors, SU, and TZD comparator groups, using the propensity score (PS) of each comparator based on 7741 people in the assessed drug SGLT-2 inhibitor group. SGLT-2 inhibitors were associated with a higher risk of genital infections than DPP-4 inhibitors (HR: 2.39, 95% CI: 2.07-2.76), SU (HR: 3.23, 95% CI: 2.73-3.81), and TZD (HR: 3.23, 95% CI: 2.35-4.44), as an add-on therapy to metformin. Similar results were observed for the risk of urinary tract infections. In conclusion, SGLT-2 inhibitors are significantly associated with a higher risk of genital and urinary tract infections compared to DPP-4 inhibitors, SU, and TZD.

Depression risk associated with the use of 5α-reductase inhibitors versus α-blockers: A retrospective cohort study in South Korea.

BACKGROUND: One of the most prescribed treatments for benign prostatic hyperplasia (BPH) is 5α-reductase inhibitors (5ARI). Europe experienced recent safety issues involving 5ARI and depression symptoms, with similar findings being seen in Western countries. The South Korea has updated the drug label in accordance with European recommendations, but the relevant evidence was insufficient. This study compared the use of 5ARI versus α-blocker (AB) as a treatment for BPH and related risks of depression to provide evidence based on the Korean population. METHODS: This was a retrospective cohort study using South Korea's Health Insurance Review & Assessment Service claim data from 2011 to 2017. New patients diagnosed in men with BPH and taking medications that contained either 5ARI or AB between July 1, 2013, and June 30, 2015, were included (n = 1,461 5ARI; n = 18,650 AB). The primary outcome was depression defined per the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10: F32-34, F38, F412, F432). Logistic regression was used to implement 1:1 propensity score (PS) matching of patients taking 5ARI to those taking AB to adjust for confounding. Cox proportional hazard models were used to compare the risk of depression associated with 5ARI versus AB. RESULTS: Balance in baseline characteristics between the treatment groups were achieved within PS matched pairs (1,461 pairs). Compared to the AB medication group, the 5ARI group had lower depression (HR: 0.69, 95% CI: [0.51-0.92]). However, we could not find a clinically relevant, statistical difference after PS matching (HR: 0.91, 95% CI: [0.61-1.36]). CONCLUSIONS: The risk of depression associated with 5ARI was not meaningfully different from AB in Korea, which suggests that medical officials should provide the most appropriate medication for BPH patients by considering both treatment benefits and depression risk.

Risk Management for the 21st Century: Current Status and Future Needs.

Global adoption of risk management principles outlined in the International Conference on Harmonisation (ICH) E2E guideline and the Council for International Organizations of Medical Sciences (CIOMS) Working Group VI guidance introduced greater proactivity and consistency into the practice of pharmacovigilance and benefit-risk management throughout the lifecycle of a drug. However, following the release of these guidelines there have been important advances in the science and practice of risk minimisation itself, especially in terms of how risk minimisation measures (RMMs) are designed, implemented, disseminated and evaluated for effectiveness in real-world healthcare settings. In this article, we describe how the field of design, implementation, dissemination and evaluation of RMMs has advanced in recent years while highlighting current areas of challenge and possible solutions. Where possible we cite global examples to demonstrate how evidence-based approaches have informed the development of RMMs. In this context, while taking into consideration local healthcare system policies and national legislations, we conclude with a call for a global effort to harmonise certain areas that focus on, but are not limited to, standardising certain terms and definitions, consistent application of robust methodologies, and outline of best practices for risk minimisation design, implementation, and dissemination.

Effects of in utero exposure to DI(n-Butyl) phthalate on development of male reproductive tracts in Sprague-Dawley rats.

The purpose of this study was to determine the effects of di(n-butyl) phthalate (DBP) administration on male reproductive organ development in F1 Sprague-Dawley rats following in utero exposure. During gestation days (GD) 10-19, pregnant rats were administered daily, orally, DBP at 250, 500, or 700 mg/kg or flutamide (1, 12.5, or 25 mg/kg/d) as a positive control. The male offspring were sacrificed at 31 d of age. DBP and flutamide dose-dependently significantly increased the incidence of hypospadias and cryptorchidism in F1 male offspring. The weights of testes and accessory sex organs (epididymides, seminal vesicles, ventral prostate, levator ani plus bulbocavernosus muscles (LABC), and Cowper's glands) were significantly reduced in DBP-treated animals. Furthermore, cauda agenesis of epididymides and ventral prostate atrophy were observed in high-dose 700-mg/kg DBP males. Anogenital distance (AGD) and levels of dihydrotestosterone (DHT) and testosterone were significantly decreased in the DBP (700 mg/kg/d)-treated groups. In particular, the expression of androgen receptor (AR) and 5α-reductase type 2 in the proximal penis was markedly depressed following administration of DBP (700 mg/kg/d) or flutamide (25 mg/kg/d). The expression of sonic hedgehog (Shh) in the urethral epithelium of the proximal penis was significantly less in the DBP (700 mg/kg/d)- or flutamide (25 mg/kg/d)-treated groups. In addition, DBP dose-dependently significantly increased the expression of estrogen receptor (ER α) in the undescended testis. Data demonstrated that in utero exposure to DBP produced several abnormal responses in male reproductive organs, and these effects may be due to disruption of the stage-specific expression of genes related to androgen-dependent organs development.

Functional role of phospholipase D (PLD) in di(2-ethylhexyl) phthalate-induced hepatotoxicity in Sprague-Dawley rats.

Phospholipase D (PLD) is an enzyme that catalyzes the hydrolysis of phosphatidyl choline (PC) to generate phosphatidic acid (PA) and choline. PLD is believed to play an important role in cell proliferation, survival signaling, cell transformation, and tumor progression. However, it remains to be determined whether enhanced expression of PLD in liver is sufficient to induce hepatotoxicity. The aim of this study was to investigate the possible role of PLD in di(2-ethylhexyl) phthalate (DEHP)-induced hepatotoxicity in Sprague-Dawley rats. The phthalate, DEHP (500 mg/kg/d), was administered orally, daily to prepubertal rats (4 wk of age, weighing approximately 70-90 g) for 1, 7, or 28 d. In this study, protein expression levels of PLD1/2, peroxisome proliferator-activated receptor (PPAR), and cytochrome P-450 (CYP) were determined by Western blot analysis using specific antibodies. Liver weight was significantly increased in the DEHP treatment groups. Immunohistochemical analysis demonstrated that DEHP produced strong staining of proliferating cell nuclear antigen (PCNA) at 28 d of exposure, suggestive of hepatocyte proliferation. A significant rise in PLD1/2 expression was observed in liver of DEHP-exposed rats after 7 d. Further, PPARα, constitutive androstane receptor (CAR), pregnane X receptor (PXR), and CYP2B1 protein expression levels were markedly elevated in DEHP-treated groups. Our results suggest that DEHP significantly enhanced the expression of PLD, which may be correlated with PPARα-induced hepatotoxicity through a complex interaction with nuclear receptors including CAR and PXR.

Comparative nephrotoxicitiy induced by melamine, cyanuric acid, or a mixture of both chemicals in either Sprague-Dawley rats or renal cell lines.

Acute nephrotoxicities of melamine (MEL), cyanuric acid (CA), and a mixture of both melamine and cyanuric acid (MC) were comparatively investigated in male Sprague-Dawley rats at 5 doses each with 10-fold dose interval as follows: MEL at 0.0315, 0.315, 3.15, 31.5, and 315 mg/kg; CA at 0.025, 0.25, 2.5, 25, and 250 mg/kg, and MC: [1×: (0.0315 + 0.025), 10×: (0.315 + 0.25), 100×: (3.15 + 2.5), 1000×: (31.5 + 25), and (315 + 250) mg/kg]. No marked adverse effects in renal function were observed in animals treated with MEL alone or CA alone, but evidence related to nephrotoxicity was noted in rats administered MC. Renal calculi and increased kidney weights were found in rats 7 d after daily oral administration of MC. Blood urea nitrogen (BUN) and creatinine were significantly elevated in the high dose MC groups at 100× or 1000×. In addition, elevated numbers of white blood cells (WBC), neutrophils, and lymphocytes in vivo and increased levels of prostaglandin E(2) (PGE(2)) in vitro were found in the MC group. Based on these data, the NOAEL (no-observed-adverse-effect level) for nephrotoxicity for MC was estimated to be 3.15 mg/kg body weight (bw)/d (MEL) plus 2.5 mg/kg bw/d (CA). If a safety factor of 1000 or more were applied to NOAEL, tolerable daily intake (TDI) would be 0.00315 and 0.0025 mg/kg/d or less for MEL and CA, respectively, which is far below the TDI of 0.2 mg/kg/d set by World Health Organization (WHO). In addition, in vitro cytotoxicity assays showed that the ACHN human renal adenocarcinoma cell line was more sensitive to MEL, CA, and MC than the MDCK canine kidney epithelial cell line. The 24-h half maximal inhibitory concentration (IC(50)) values for MEL (4792, 2792 µg/ml) were less than those of CA (9890, 6725 µg/ml, respectively) in MDCK and ACHN cell lines, suggesting that MEL may be more cytotoxic than CA. Furthermore, the 24-h IC(50) value for MC was found to be 208 µg/ml in ACHN cells. Data suggest that NOAELs based upon acute nephrotoxic parameters for MC were low, which might require further reassessment of the current TDI.

OECD validation of phase-3 Hershberger assay using the stimulated weanling male rat in Korea.

The OECD has proposed a new, validated test guideline with the stimulated weanling male Hershberger assay to avoid the surgical castration step. In the present study, we assessed the relevance and reliability of the stimulated weanling Hershberger assay in four stages. All chemicals except for testosterone propionate (TP) were orally administered to sexually immature male rats of 22 days old for 10 days. The weights of four mandatory accessory sex organs, two additional reproductive tissues and optional systemic organs were evaluated. At the first two stages, TP, as reference androgen, significantly increased the weights of epididymides and accessory sex organs (ASO) at 1.0 mg kg(-1) and flutamide (FLU), as a positive anti-androgen control, decreased the TP-stimulated organ weights at 3.0 mg kg(-1). At stage 3, trenbolone (40 mg kg(-1)), an anabolic steroid, significantly increased ASO weights, and weak anti-androgens (DDE and linuron) decreased the TP-stimulated ASO weights at each high dose. The above results were confirmed in a blind test with coded substances provided by OECD. Compared with results from our previous castrated male assay, the intact weanling version is less sensitive than the castrated male version, in terms of a smaller response at the reference dose of TP or FLU. However, this study suggests that the stimulated weanling Hershberger assay can detect the effects of both potent and weak anti-androgens on androgen-producing and androgen-dependent tissues.

Potencies of bisphenol A on the neuronal differentiation and hippocampal neurogenesis.

Endocrine-disrupting chemicals (EDC) produce adverse effects on reproductive and immune function or neurological behavior, and may also induce cancer. The environmental EDC bisphenol A (BPA) is widely used in the manufacture of plastics and epoxy resins. BPA affects reproductive organ growth and development, but the potential adverse effects of BPA on neuronal development are not fully understood. Here, BPA concentration-dependently decreased proliferation of murine-derived multipotent neural progenitor cells (NPC), and high concentrations produced cytotoxicity. In contrast, low concentrations of BPA, which possess estrogenic activity, stimulated NPC differentiation into a neuronal phenotype. BPA treatment did not affect neonatal brain development in F1 mice. However, BPA treatment (20 mg/kg) accelerated formation of the dentate gyrus in postnatal day 1 mice. Prenatal and postnatal BPA treatment did not affect adult hippocampal neurogenesis in the dentate gyrus in 8-wk-old mice. Data indicate that BPA stimulates neuronal differentiation and might disrupt neonatal brain development.

An exposure assessment of di-(2-ethylhexyl) phthalate (DEHP) and di-n-butyl phthalate (DBP) in human semen.

Levels of the phthalates such as di(2-ethylhexyl) phthalate (DEHP), mono(2-ethylhexyl) phthalate (MEHP, a major metabolite of DEHP), di-n-butyl phthalate (DBP), mono-n-butyl phthalate (MBP, a major metabolite of DBP), and phthalic acid (P, (a common metabolite of phthalates, including DEHP and DBP) were determined in the semen samples of 99 healthy volunteers without known prior medicosurgical history. Samples were obtained from young men (age 20-25 yr) who visited a clinic, and the semen concentrations of phthalates were measured using ultra-performance liquid chromatography (UPLC) and tandem mass spectrometry (MS/MS). UPLC/MS/MS showed that mean concentrations in semen samples were 1.07 microg/ml for MEHP, 0.61 microg/ml for DEHP, 0.39 microg/ml for PA, 0.06 microg/ml for MBP, and 0.003 microg/ml for DBP. The concentration of MEHP (the metabolite of DEHP) was highest, and the concentrations of the metabolites including MEHP, MBP, and PA were higher than actual concentrations of parent DEHP and DBP. These findings suggest the detection of phthalates in healthy human semen might require further investigation for effects on human fertility.

Effects of gestational exposure to decabromodiphenyl ether on reproductive parameters, thyroid hormone levels, and neuronal development in Sprague-Dawley rats offspring.

Polybrominated diphenyl ethers (PBDE) are a class of brominated flame retardants that are recognized as global environmental contaminants with potential adverse effects on human health. This study examined the effects of prenatal exposure to PBDE on reproductive organs, neuronal development, and levels of thyroid hormones. Pregnant rats were exposed to the vehicle or deca-bromodiphenyl ether (BDE) (BDE-209; 5, 40, or 320 mg/kg body weight/d) during gestation days (GD) 6-18. There was a significant decrease in body weight gain in F1 male offspring exposed to high-dose (320 mg/kg) BDE-209. Significant increases in thyroid weight and a decrease in adrenal weight were observed in high-dose BDE-209. Thyroxine (T4) concentrations were significantly lower in F1 female offspring exposed to BDE-209 at postnatal day (PND) 42. This reduction was more pronounced in the group exposed to higher doses. A low dose (5 mg/kg) of BDE-209 significantly reduced serum estradiol concentration in female offspring but did not affect testosterone levels in males. There was no significant effect on hippocampal neurogenesis in BDE-209 treatment groups. In conclusion, there was no apparent association between thyroid hormone concentrations and low birth weight in F1 rats after gestational exposure to BDE-209.

Exposure assessment of polybrominated diphenyl ethers (PBDE) in umbilical cord blood of Korean infants.

This study examined the levels of polybrominated diphenyl ethers (PBDE) in the umbilical cord blood of infants, and investigated the relationship between PBDE concentration and thyroid hormone levels. The concentration of PBDE were measured in the cord blood samples of 108 infants collected in Cheil Woman's Hospital, Seoul, Korea, in 2007. Of 108 pregnant woman reported, the average age was 31.9 +/- 3.54 yr (range 20-42 yr). The mean body weight of the infants was 3.15 +/- 0.57 kg (1.89-4.43 kg), and no birth defects were documented. The concentrations of the total PBDEs (7 congeners) found in the umbilical cord blood averaged 8.377 +/- 6.381 ng/g lipid, ranging from not determined (ND) to 29.407 ng/g lipid. Of the seven congeners detected, BDE-47 (4.571 +/- 2.903 ng/g lipid) accounted for the majority (38% of total PBDE) of total PBDE, followed in descending order by BDE-153 (3.080 +/- 2.231 ng/g lipid) and BDE-183 (2.933 +/- 2.386). There was no apparent correlation between the serum PBDE levels and thyroid hormone concentrations. Similarly, there was no apparent relationship between the infant thyroxine (T4) levels and four prevalent PBDE congener concentrations. Data suggest that the concentration of PBDE in umbilical cord blood of Korean infants is similar to or lower than concentrations reported from North America. In addition, PBDE readily crossed the blood placenta barrier. Therefore, further study on the relationship between the maternal and fetal blood concentrations of PBDE is recommended for a more comprehensive exposure assessment of PBDE in Koreans.

Metabolomics approach to risk assessment: methoxyclor exposure in rats.

The primary objective of this study was to develop exposure biomarkers that "correlate with the endocrine-disrupting effects induced by methoxyclor (MTC), an organochlorine pesticide, using" urinary (1)H nuclear magnetic resonance (NMR) spectral data. Exposure biomarkers play an important role in risk assessment. MTC is an environmental endocrine disruptor with estrogenic, anti-estrogenic, and anti-androgenic properties. A new approach of proton nuclear magnetic resonance ((1)H NMR) urinalysis using pattern recognition was proposed for exposure biomarkers of MTC in female rats. The endocrine disruptor was expected to induce estrogenic effects in a dose dependent manner which, was confirmed by the uterotrophic assay. MTC [50, 100, or 200 m g/kg/d, orally (p.o.) or subcutaneously (s.c.)] was administered to ovariectomized female Sprague-Dawley (SD) rats for 3 d consecutively and urine was collected every 24 h. The animals were sacrificed 24 h after the last dose. All animals treated orally with MTC showed a significant increase in uterine and vaginal weight at all doses. However, in the s.c. route, only a high dose of 200 mg MTC/kg induced a significant increase in uterine and vaginal weight. (1)H NMR spectroscopy revealed evident separate clustering between pre- and post-treatment groups using global metabolic profiling through principal component analysis (PCA) and partial least square (PLS) discrimination analysis (DA) after different exposure routes. With targeted profiling, the endogenous metabolites of acetate, alanine, benzoate, lactate, and glycine were selected as putative exposure biomarkers for MTC. Data suggest that the proposed putative exposure biomarkers may be useful in a risk assessment of the endocrine-disrupting effects produced by MTC.

OECD validation of phase 3 Hershberger assay in Korea using surgically castrated male rats with coded chemicals.

As a participating laboratory for the OECD Hershberger validation program, we conducted a phase 3 trial to test the reliability of the Hershberger assay using coded substances. Male Sprague-Dawley rats were castrated at 6 weeks of age and allowed to recover for 8 days. All the coded substances were administered orally once daily for 10 consecutive days. In the antagonist version of the assay, 0.4 mg kg(-1) of testosterone propionate (TP), a reference androgen, was co-administered with the coded compounds C, D, H, I or K, by a subcutaneous injection. As anticipated, TP alone produced statistically significant increases in the five mandatory accessory sex organ weights. The coded substance L (trenbolone 40 mg kg(-1)), the test agonist, caused significant increases in the weights of the androgen-dependent tissues. The five coded compounds, p,p'-DDE at two doses (codes C and I), linuron at two doses (codes D and K) and flutamide (code H), all significantly decreased the weights of the TP-stimulated sex organs. These results suggest the OECD Hershberger assay to be a reliable screening method for detecting androgen agonists and antagonists.

Time-response effects of testicular gene expression profiles in Sprague-Dawley male rats treated with di(n-butyl) phthalate.

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.

Suppressive effects of bisphenol A on the proliferation of neural progenitor cells.

Endocrine disruptors (EDs) exert adverse effects on reproductive and immune function or neurological behavior. Bisphenol A (BPA), one of the environmental EDs, is widely used in the manufacture of plastics and epoxy resins. Studies reported that BPA affects reproductive organ growth and development. However, the potential adverse effects of BPA on neuronal development have not been fully explored. In this study, the potent harmful effects of BPA were investigated on the murine-derived multipotent neural progenitor cells (NPCs). Pretreatment of BPA significantly decreased proliferation of NPCs in a concentration-dependent manner. Moreover, at a high concentration (> 400 microM), BPA was cytotoxic to NPCs. However, the low concentrations of BPA, previously shown to exert estrogenic actions, did not affect the proliferation of NPCs. BPA altered the activation of extracellular signal-regulated kinases and c-Jun-N-Kinases in a different manner without affecting activities of p38 kinases. It was also found that reactive oxygen species (ROS) were elevated in NPCs exposed to high concentrations of BPA, indicating oxidative stress-related cytotoxicity. These data show adverse effects of BPA on the nervous system and potentially on neonatal brain development.

Di(2-ethylhexyl) phthalate induces apoptosis through peroxisome proliferators-activated receptor-gamma and ERK 1/2 activation in testis of Sprague-Dawley rats.

Di(2-ethylhexyl) phthalate (DEHP) is a well-known hepatic and reproductive toxicant whose toxicity may be mediated by peroxisome proliferators-activated receptor (PPAR). This study examined the effects of DEHP on the expression of PPAR-regulated genes involved in testicular cells apoptosis. Sprague-Dawley male rats were treated orally with 250, 500, or 750 mg/kg/d DEHP for 28 d, while control rats were given corn oil. The levels of cell cycle regulators (pRb, cyclins, CDKs, and p21) and apoptosis-related proteins were analyzed by Western blot analysis. The role of PPAR-gamma (PPAR-gamma), class B scavenger receptor type 1 (SR-B1), and ERK1/2 was further studied to examine the signaling pathway for DEHP-induced apoptosis. Results showed that the levels of pRB, cyclin D, CDK2, cyclin E, and CDK4 were significantly lower in rats given 500 and 750 mg/kg/d DEHP, while levels of p21 were significantly higher in rat testes. Dose-dependent increases in PPAR-gamma and RXRalpha proteins were observed in testes after DEHP exposure, while there was a significant decrease in RXRgamma protein levels. In addition to PPAR-gamma, DEHP also significantly increased SR-B1 mRNA and phosphorylated ERK1/2 protein levels. Furthermore, DEHP treatment induced pro-caspase-3 and cleavage of its substrate protein, poly(ADP-ribose) polymerase (PARP), in a dose-dependent manner. Data suggest that DEHP exposure may induce the expression of apoptosis-related genes in testes through induction of PPAR-gamma and activation of the ERK1/2 pathway.