Morphine compromises androgen biosynthesis by immature Leydig cells from pubertal rat testes in vitro.

Morphine is an analgesic in the opiate family, isolated from many plants. It can inhibit androgen biosynthesis by Leydig cells. Whether morphine directly inhibits androgen biosynthesis and underlying mechanism remains unclear. To investigate the influence of morphine on androgen secretion by rat immature Leydig cells (ILCs) and possible mechanism. Rat ILCs were treated with 0.5-50 µM morphine for 3 h in vitro. Morphine at ≥0.5 µM significantly reduced total androgen secretion. Morphine at 50 µM also compromised luteinizing hormone (LH, 10 mg/kg), 8Br-cAMP (1 mM), and 22R-hydroxycholesterol (20 µM) stimulated total androgen, androstanediol, and testosterone secretion, without affecting pregnenolone, progesterone, androstenedione mediated androgen secretion and testosterone and dihydrotestosterone mediated androstanediol secretion. Further analysis revealed that morphine at ≥0.5 µM downregulated Star expression and at ≥5 µM downregulated Cyp11a1 expression. Morphine also significantly reduced STAR (≥0.5 µM) and reduced CYP11A1 (≥5 µM) levels. 0.5 µM naloxone significantly antagonized morphine-mediated action. In conclusion, morphine might cause side effects by suppressing androgen biosynthesis via u opioid receptor.

Differential metabolic networks in three energy substances of flaxseed (Linum usitatissimum L.) during germination.

Germinated flaxseed (Linum usitatissimum L.) is an essential potential food ingredient, but the major energy substances (proteins, lipids, and carbohydrates) metabolites and metabolic pathways are unknown. Comprehensive metabolomic analyses were performed using Fourier transform infrared spectroscopy and high-performance liquid chromatography mass spectrometry on flaxseed from 0 to 7 d. Additionally, the critical metabolites pathways networks of three energy substances metabolites during flaxseed germination were exhibited. The results showed that arginine was the most active metabolite during germination, strongly associated with the arginine biosynthesis and arginine and proline metabolism pathways. Carbohydrates predominantly comprised sucrose on 0-3 d, which participated in galactose metabolism and starch and sucrose metabolism. The main flaxseed phospholipid molecules were phosphatidic acid, phosphatidylethanolamine, lysophosphatidic acid, and lysophosphatidylcholine during germination. This study underscores the paramount metabolic pathways in proteins, lipids and carbohydrates were arginine and proline metabolism, linoleic acid metabolism, arachidonic acid metabolism, and ascorbate and aldarate metabolism during germination.

Inhibition of soluble epoxide hydrolase relieves adipose inflammation via modulating M1/M2 macrophage polarization to alleviate airway inflammation and hyperresponsiveness in obese asthma.

Obesityincreasestheriskofasthma and tends to enhance the asthma severity, however, its mechanism is not fully elucidated. The expansion of adipose tissue in obesity is accompanied by the accumulation of adiposetissue macrophages (ATMs) that could contribute to alow-gradeinflammationstate. In this study, we researched the regulatory role of soluble epoxide hydrolase (sEH) on ATMs-mediated inflammation in obese asthma. A mouse model of obese asthma that induced by high-fat diet (HFD) feeding and Ovalbumin (OVA) sensitization was employed to investigate the effects of AUDA, a sEH inhibitor (sEHi), on airway inflammation, airway hyperresponsivenesss (AHR) and pulmonary pathological changes. In addition to alleviating the key features of asthma in obese mice, we confirmed that AUDA reduced the expression of pro-inflammatory factor, such as interleukin-1ß (IL-1ß), interleukin-6 (IL-6) and tumornecrosisfactor-α (TNF-α) in adipose tissue and serum. Moreover, AUDA could remarkedly reduce Lipopolysaccharide (LPS)-elevated IL-1ß, IL-6 and TNF-α in RAW264.7 macrophage cells. Mechanistically, AUDA effectively reduced inflammation in adipose tissue, resulting in reduced systemic inflammation, by inhibiting M1-type macrophage polarization and promoting M2-type macrophage polarization. These processes were found to act through ERK1/2 signaling pathway. Herein, we proved that inhibition of sEH expression helped to mitigate multiple parameters of obese asthma by regulating the balance of M1/M2 macrophage polarization in adipose tissue.

Indication of the color change on the oxidation properties of fragrant rapeseed oil during shelf storage.

The cause and trend of color change and their links to oxidative properties were investigated by simulating shelf storage conditions for fragrant rapeseed oils (FROs). Under illumination, the L* value gradually increased with the storage time. The a* and b* values showed different trends depending on brands. The photodegradation rates of chlorophylls were 8.6 âˆ¼ 15 times higher than those of carotenoids. The change in color of FROs was mainly caused by the light-induced photodegradation of chlorophyll. Compared with the hydroperoxides, the contents of some secondary oxidation products [i.e., 2-butenal, octane, (Z)-2-octene, 2,4-octadiene, (Z)-2-heptenal, (E, E)-2,4-heptadienal, and (E)-2-decenal] were more closely associated with the color variation with correlation coefficients of 0.6 âˆ¼ 0.94. Significant negative correlation was found between α-tocopherol content and oil color difference. Therefore, illumination was the main reason for the color degradation of the FROs. The varying degree of color difference was strongly linked to the quality deterioration caused by oxidation.

The complete mitochondrial genome of Anthrenus museorum (Coleoptera: Bostrichiformia: Dermestidae) from China.

Dermestid beetles (Coleoptera: Bostrichiformia: Dermestidae) are important pests of various storage products and pose a potential threat to international trade. In this study, the whole mitogenome of Anthrenus museorum was first sequenced and annotated and was found to have the same gene order observed in known dermestid beetles. It comprised 13 protein-coding genes (PCGs), 22 transfer RNAs, 2 ribosomal RNAs and a control region. The typical ATN start codon was observed in all PCGs, except for ND3 (TTG), and all 13 PCGs showed three types of stop codons (TAA, TAG, and T-). Phylogenetic analysis based on the PCGs indicated that the relationships within Bostrichiformia were reconstructed, with the exception of one early emerging species of Bostrichidae that actually makes the group polyphyletic, as (Dermestidae + (Bostrichidae + Anobiidae)). Moreover, it revealed a close relationship between A. museorum and A. verbasci using maximum likelihood and Bayesian inference analysis.

Multi-domain-fusion deep learning for automatic modulation recognition in spatial cognitive radio.

Automatic modulation recognition (AMR) is a critical technology in spatial cognitive radio (SCR), and building high-performance AMR model can achieve high classification accuracy of signals. AMR is a classification problem essentially, and deep learning has achieved excellent performance in various classification tasks. In recent years, joint recognition of multiple networks has become increasingly popular. In complex wireless environments, there are multiple signal types and diversity of characteristics between different signals. Also, the existence of multiple interference in wireless environment makes the signal characteristics more complex. It is difficult for a single network to accurately extract the unique features of all signals and achieve accurate classification. So, this article proposes a time-frequency domain joint recognition model that combines two deep learning networks (DLNs), to achieve higher accuracy AMR. A DLN named MCLDNN (multi-channel convolutional long short-term deep neural network) is trained on samples composed of in-phase and quadrature component (IQ) signals, to distinguish modulation modes that are relatively easy to identify. This paper proposes a BiGRU3 (three-layer bidirectional gated recurrent unit) network based on FFT as the second DLN. For signals with significant similarity in the time domain and significant differences in the frequency domain that are difficult to distinguish by the former DLN, such as AM-DSB and WBFM, FFT (Fast Fourier Transform) is used to obtain frequency domain amplitude and phase (FDAP) information. Experiments have shown that the BiGUR3 network has superior extraction performance for amplitude spectrum and phase spectrum features. Experiments are conducted on two publicly available datasets, the RML2016.10a and RML2016.10b, and the results show that the overall recognition accuracy of the proposed joint model reaches 94.94% and 96.69%, respectively. Compared to a single network, the recognition accuracy is significantly improved. At the same time, the recognition accuracy of AM-DSB and WBFM signals has been improved by 17% and 18.2%, respectively.

Trichlorfon blocks androgen synthesis and metabolism in rat immature Leydig cells.

Trichlorfon is a widely used organophosphorus insecticide. It has been reported that it has reproductive toxicity to animal models. However, whether trichlorfon affects testosterone biosynthesis and metabolism remains unclear. In this study, we explored the effects of trichlorfon on the steroidogenesis and the expression of genes in androgen biosynthetic and metabolic cascades in immature Leydig cells isolated from pubertal male rats. Immature Leydig cells were treated with trichlorfon (0.5-50 µM) for 3 h. Trichlorfon significantly inhibited total androgen output under basal condition at 5 and 50 µM, and under LH- and cAMP-stimulated conditions at 50 µM. Trichlorfon also downregulated the expression of Star, Sod2, and Gpx1 and their proteins at 5 and 50 µM and the expression of Cyp11a1, Hsd3b1, Cyp17a1, and Srd5a1 at 50 µM. Trichlorfon significantly inhibited total androgen output at 50 µM, which was partially reversed by 400 µg/ml vitamin E, which alone had no effects on androgen output. In conclusion, trichlorfon downregulates the expression of steroidogenesis-related genes and antioxidants, which leads to a decrease in androgen production in rat immature Leydig cells.

Effect of germination pretreatment on the physicochemical properties and lipid concomitants of flaxseed oil.

This study investigated the effects of germination pretreatment on the physicochemical properties, lipid concomitants, and antioxidant activity of flaxseed oil in three varieties. The results indicated that the oil content of flaxseed decreased by 2.29-7.40% during the 5 days germination period. Germinated flaxseed oil showed a significantly higher acid value and lower peroxide value. The unsaturated fatty acid content was slightly increased by germination. Germination pretreatment resulted in significant increases in the α-tocopherol, stigmasterol, pigments, total phenols, and antioxidant activity. As germination time progressed to 5 days, α-tocopherol which was traditionally recognized as having the highest antioxidant activity form of vitamin E in humans increased from 3.07-6.82 mg kg-1 to 258.11-389.78 mg kg-1. Germinated oil had 1.63 to 2.05 times higher stigmasterol content than non-germinated oil. The chlorophyll and carotenoid also increased exponentially. The total phenol content of flaxseed oil increased from 64.29-75.85 mg kg-1 to 236.30-297.78 mg kg-1. Germinated flaxseed oil showed important antioxidant activity. Compared with other varieties during germination, the oil from Gansu showed a higher level of α-linolenic acid, tocopherols, and carotenoid, and a maximum increase level of tocopherols and phytosterols. The comprehensive evaluation of germination time by correlation and principal component analysis showed that when germination time exceeded 2 days, the lipid concomitants and antioxidant capacity of flaxseed oil were significantly improved.

Dynamics of composition, structure, and metabolism of three energy substances in flaxseed (Linum usitatissimum L.) during germination.

The composition and structure changes of three energy substances (protein, lipid, and sugar) and minerals during flaxseed germination were investigated. Na, Ca, Fe, and total free amino acids fluctuating increased and peaked at 7 d. Oil and ɑ-linolenic acid contents increased initially and reached the maximal increment by 14.8 % and 1.4 % (p < 0.05) at 2 d, after which it declined. Soluble sugar mainly consisted of sucrose (50.47 %-72.77 %), glucose, and fructose during germination. Semi-cylindrical depression was enhanced on flaxseed granule surface, and oil bodies distribution from relatively uniform toward cell wall during 0-2 d. Protein order and stability were varied firstly, then grew steadily at 4-7 d and peaked at 7 d. Metabolic sequence (sugar, protein, and lipid) and related tricarboxylic acid pathway were proposed. Conclusively, germinated flaxseed at 2 and 4 d had higher physicochemical and structural properties, which could serve as high-quality resources for lipid and protein processing respectively.

Strong and Durable Wood Designed by Cell Wall Bulking Combined with Cell Lumen Filling.

Traditional wood-polymer composite (WPC) based on the in situ polymerization of ethylene unsaturated monomers in the cellular cavity of wood is significant for the high-value-added utilization of low-quality wood. However, this type of WPC has the problems of volatile monomers, low conversion rates, odor residue, and poor compatibility between the polymer and wood interface, which hinder its promotion and application. In this study, a two-step process of cell wall bulking in combination with cell lumen filling was prepared to modify wood using Maleic anhydride (MAN) as the bulking agent and GMA-EGDMA (molar ratio 2:1) as the active monomer system. The results indicate that the modulus of rupture (MOR) (125.19 ± 8.41 MPa), compressive strength (116.38 ± 7.69 MPa), impact toughness (55.4 ± 2.95 KJ m-2), and hardness (6187 ± 273 N) of the bulking-filling wood composite materials were improved by 54%, 56%, 36%, and 66%, respectively, compared with those of poplar wood. These properties were superior to those of the traditional styrene (PSt)-WPC and even exceeded the performance of Xylosma congesta (Lour.) Merr, a high-quality wood from northeast China. Meanwhile, the mass loss of wood composite materials with bulking-filling treatment was only 2.35 ± 0.05%, and the internal structure remained intact, presenting excellent decay resistance. Additionally, the treatment also significantly improved the thermal and dimensional stability of the wood composites. This study provides a theoretical basis and guidance for realizing the high-value-added application of low-quality wood and the preparation of highly durable wood-based composites.

Chemicals of environmental concern as inhibitors of human placental 3ß-hydroxysteroid dehydrogenase 1 and aromatase: Screening and docking analysis.

Many environmental pollutants act as endocrine-disrupting compounds by inhibiting human placental 3ß-hydroxysteroid dehydrogenase/Δ5-4 isomerase type 1 (HSD3B1) and aromatase (CYP19A1) activities. In this study, we screened 13 chemicals of environmental concern for their ability to inhibit human HSD3B1 and CYP19A1 by measuring the conversion of pregnenolone to progesterone for HSD3B1 activity and the conversion of testosterone to 17ß-estradiol for CYP19A1 activity in human JEG-3 choriocarcinoma cell microsomes. HSD3B1 had an apparent Km of 0.323 µM and an apparent Vmax of 0.111 nmol/mg/min and CYP19A1 had an apparent Km of 56 nM and an apparent Vmax of 0.177 nmol/mg protein/min. 17ß-Estradiol, bisphenol A, and bisphenol AF competitively inhibited HSD3B1 with Ki values of 0.8, 284.1, and 141.2 µM, respectively, while diethylstilbestrol had a mixed inhibition on human HSD3B1 with the Ki of 8.0 µM. Ketoconazole, bisphenol A, and bisphenol AF noncompetitively inhibited CYP19A1 with Ki values of 10.3, 54.4, and 45.7 µM, respectively, while diethylstilbestrol and zearalenone competitively suppressed CYP19A1 with Ki values of 63.0 and 16.6 µM, respectively. Docking analysis showed that 17ß-estradiol, diethylstilbestrol, bisphenol A, and bisphenol AF bound the steroid binding pocket facing the catalytic residues Y155 and K159 of HSD3B1, and that ketoconazole, bisphenol A, and bisphenol AF bound heme binding pocket while diethylstilbestrol and zearalenone bound the steroid binding site of CYP19A1. In conclusion, 17ß-estradiol, diethylstilbestrol, bisphenol A, and bisphenol AF are human HSD3B1 inhibitors, and ketoconazole, zearalenone, diethylstilbestrol, bisphenol A, and bisphenol AF are human CYP19A1 inhibitors.

Shp2 regulates PM2.5-induced airway epithelial barrier dysfunction by modulating ERK1/2 signaling pathway.

The impact of fine particulate matter (PM2.5) on public health has received increasing attention. Through various biochemical mechanisms, PM2.5 alters the normal structure and function of the airway epithelium, causing epithelial barrier dysfunction. Src homology domain 2-containing protein tyrosine phosphatase 2 (Shp2) has been implicated in various respiratory diseases; however, its role in PM2.5-induced epithelial barrier dysfunction remains unclear. Herein, we assessed the regulatory effects of Shp2 on PM2.5-mediated epithelial barrier function and tight junction (TJ) protein expression in both mice and human pulmonary epithelial (16HBE) cells. We observed that Shp2 levels were upregulated and claudin-4 levels were downregulated after PM2.5 stimulation in vivo and in vitro. Mice were exposed to PM2.5 to induce acute lung injury, and disrupted epithelial barrier function, with decreased transepithelial electrical resistance (TER) and increased paracellular flux that was observed in 16HBE cells. In contrast, the selective inhibition or knockdown of Shp2 retained airway epithelial barrier function and reversed claudin-4 downregulation that triggered by PM2.5, and these effects may occur through the ERK1/2 MAPK signaling pathway. These data highlight an important role of Shp2 in PM2.5-induced airway epithelial barrier dysfunction and suggest a possible new course of therapy for PM2.5-induced respiratory diseases.

Functional Properties and Structural Characteristics of Starch-Fatty Acid Complexes Prepared at High Temperature.

The effects of fatty acid type (myristic, palmitic, stearic, oleic, linoleic, and linolenic acid) on the characteristics of starch-lipid complexes under high temperature were investigated. Fatty acids with a shorter carbon chain or a greater number of double bonds contributed to the formation of V-type starch-lipid complexes. The thermostability of starch-unsaturated fatty acid (UFA) complexes prepared at high temperature was increased compared with those obtained at lower temperature. Resistant starch (RS) contents and melting temperatures had a strong significant positive correlation. Complexes with better thermostability were more resistant to enzymatic hydrolysis. Among them, the starch-stearic acid complexes possessed the highest RS content. The paste of starch-linolenic acid complexes had the lowest internal friction and the strongest thixotropy. The broken of double bonds in UFAs probably accounted for the increased starch-lipid complexes. The crystalline, thermal, rheological, and digestion properties of samples treated at high temperature were significantly affected.

Antifibrotic Effect of a Novel Selective 11ß-HSD2 Inhibitor (WZ51) in a rat Model of Myocardial Fibrosis.

Myocardial fibrosis (MF) is one of the leading causes of end-stage heart disease. Many studies have confirmed that inflammation caused by aldosterone may play an important role in the process of MF. A selective 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2) enzyme inhibitor can reduce the inactivation of cortisol, allowing cortisol to compete for mineralocorticoid receptors. This study investigated the protective effect of a novel selective 11ßHSD2 inhibitor (WZ51) on MF and described its underlying mechanism. The administration of WZ51 in rats with MF significantly alleviated myocardial injury, accompanied by a decrease in lactate dehydrogenase and the creatine kinase myocardial band. Furthermore, WZ51 significantly inhibited the development of MF and increased the protein level of 11ß-HSD2. The results of this study demonstrate that 11ß-HSD2 plays an important pathological role in MF. Thus, WZ51 may be a potential therapeutic agent for the treatment of this condition.

Investigation on food packaging polymers: Effects on vegetable oil oxidation.

Polyethylene (PE), polypropylene (PP), polyamide (PA), and polyethylene terephthalate (PET) surfaces and particles were employed to study effects of polymer materials on linseed oil, peanut oil, rapeseed oil and sunflower seed oil oxidation. The surface types of the materials, hydroperoxide content and volatile in oils were determined by contact angle, Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry. Oils on PP surfaces underwent a more rapid oxidation, followed by PA, PE and PET. Except PP sets, this order was consistent with surface hydrophilicity of polymers. Further study using polymer particles avoiding packaging barrier suggested this was probably due to barrier factors. Although PE surfaces allowed oil to have lower content of hydroperoxides, it can promote oil hydroperoxide decomposition into volatile products. Surface types of polymer materials are correlated with oxidation of contacted oil, and these surfaces can also affect the oil secondary oxidation and the degradation of oxidation products.

An indirect analytical approach based on ATR-FTIR spectroscopy for determining the FFA content in vegetable oils.

In this study, we developed a novel approach for determining a free fatty acid (FFA) in vegetable oils using attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. FFA was converted to carboxylate species by a reaction with phthalimide potassium salt, and the linear relationship between FFA content and ATR-FTIR peak areas at 1541-1616 cm-1 (1595 cm-1 as baseline) was established. Results showed that the R 2 values obtained during calibration and validation were more than 0.99. The calibration method concurred to within ±0.035% over the range of 0.4% to 4.0% (quantitative determination of the percentage of FFA in oils, expressed as the percentage of oleic acid). In the calibration model, the root mean square error of prediction was 0.0104, the relative error was less than 0.246% and the relative average deviation was 0.386%, respectively. These indexes demonstrated that the calibration model has great accuracy, high precision and good stability. The indirect method established using ATR-FTIR has the advantages of excellent reproducibility, high exactitude, independent of oil type, simple operation and easy cleaning of the instrument surface. The slope of the verification equation between FFA prediction values and American Oil Chemists' Society's (AOCS) titration method was close to 1, R 2 value was more than 0.99. These indicators suggested that the proposed method and the AOCS method have a good correlation through AOCS titration and ATR-FTIR spectroscopy to determine validation samples parallel. In addition, for comparison, when the AOCS titration and ATR-FTIR spectroscopy methods were used for sample validation, the results indicated that the latter method is more reproducible, highly sensitive and has strong anti-disturbance. Therefore, the ATR-FTIR technique can be applied as a simple, highly sensitive, convenient and timely method for the analysis of FFAs in oils.

Morphology, structural, thermal and rheological properties of wheat starch-palmitic acid complexes prepared during steam cooking.

This work aimed to determine the changes in the morphology, complexation degree, the structural, thermal, and rheological properties of starch-fatty acid complexes during steam cooking. In this study, wheat starch with certain water and palmitic acid contents were steamed for 0.5, 1, 1.5, 2, and 2.5 h. The complexing index (CI) first decreased and then progressively increased with the prolonging of steam cooking time. The decrease in CI was associated with the decomposition of the complex layer formed on the granule surface at 0.5 h of steam cooking. The interaction between wheat starch and palmitic acid led to the change of starch crystal type. Prolonging treatment time promoted thermal stability and structural order degree. The type I and IIa complexes reached saturation and fatty acids in the interstitial space between helices increased with excessive treatment times. Rheological behavior analysis showed that the viscoelasticity and deformation degree of samples decreased and increased, respectively, with increasing steam cooking time. Results showed that the thermostability and order degree of the complex layer were lower than those of samples with long treatment times and complexing was effective during steam cooking.

Dimethoate blocks pubertal differentiation of Leydig cells in rats.

Dimethoate is an organophosphate pesticide. It is widely used in agriculture. However, whether it blocks pubertal development of Leydig cells remains unknown. In the current study, we exposed male Sprague Dawley rats with 7.5 and 15 mg kg-1 dimethoate from postnatal day 35-56. We also exposed Leydig cells isolated from 35-day-old rats for 3 h. Dimethoate reduced serum testosterone levels at 7.5 and 15 mg kg-1 but increased serum luteinizing hormone and follicle stimulating hormone levels at 15 mg kg-1. Dimethoate did not influence Leydig cell number but reduced Leydig cell size and down-regulated Star, Cyp11a1, and Hsd3b1 in Leydig cells as well as their protein expression. Dimethoate inhibited basal androgen output in a dose-dependent manner with the inhibition starting at 0.05 µM. It significantly inhibited luteinizing hormone and 8Br-cAMP stimulated androgen outputs at 50 µM. It significantly inhibited 22R-hydroxycholesterol and progesterone-mediated androgen outputs at 50 µM. Further study demonstrated that dimethoate also down-regulated the expression of Star, Cyp11a1, and Hsd3b1 at 5 or 50 µM in vitro. Dimethoate did not directly inhibit rat testicular steroidogenic enzyme activities at 50 µM. In conclusion, dimethoate targets Star, Cyp11a1, and Hsd3b1 transcription, thus blocking Leydig cell differentiation during puberty.

Acephate interferes with androgen synthesis in rat immature Leydig cells.

Acephate is an organophosphate pesticide. It is widely used. However, whether it inhibits androgen synthesis and metabolism remains unclear. In the current study, we investigated the effect of acephate on the inhibition of androgen synthetic and metabolic pathways in rat immature Leydig cells after 3-h culture. Acephate inhibited basal androgen output in a dose-dependent manner with the inhibition starting at 0.5 µM. It significantly inhibited luteinizing hormone and 8-Br-cAMP stimulated androgen output at 50 µM. It significantly inhibited progesterone-mediated androgen output at 50 µM. Further study demonstrated that acephate down-regulated the expression of Hsd3b1 and its protein at ≥ 0.5 µM, Lhcgr at 5 µM and Star at 50 µM. Acephate directly blocked rat testicular HSD3B1 activity at 50 µM. Acephate did not affect other androgen synthetic and metabolic enzyme activities as well as ROS production, proliferation, and apoptosis of immature Leydig cells. In conclusion, acephate targets LHCGR, STAR, and HSD3B1, thus blocking androgen synthesis in rat immature Leydig cells and HSD3B1 is being the most sensitive target of acephate.

Benzyl butyl phthalate non-linearly affects rat Leydig cell development during puberty.

Benzyl butyl phthalate (BBP) is a widely used plasticizer and has raised public health concerns. Here, we report the effects of BBP on the testis development during rat puberty. BBP (0, 10, 100 or 1000 mg/kg) was gavaged to 35-day-old male Sprague Dawley rats for 21 days. The serum testosterone levels, Leydig cell number, the expressions of Leydig and Sertoli cell genes and proteins were measured. The in vitro effects on steroidogenesis and gene expression in immature Leydig cells were observed. BBP significantly increased serum testosterone level at 10 mg/kg but lowered its level at 1000 mg/kg without affecting serum luteinizing hormone and follicle-stimulating hormone levels. BBP increased Leydig cell number at all doses but inhibited steroidogenic capacity per Leydig cell at 1000 mg/kg. BBP significantly increased the ratio of phosphos-AKT2 (pAKT2)/AKT2, and phosphos-ERK1/2 (pERK1/2)/ERK1/2 in the testis. Mono-benzyl phthalate (the metabolite of BBP) inhibited steroidogenesis but BBP did not affect androgen production in immature Leydig cells in vitro. In conclusion, BBP non-linearly regulates Leydig cell development by increasing Leydig cell number but inhibiting steroidogenesis.