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Steroidogenesis of gonadal cells is tightly regulated by gonadotropins. However, certain polycyclic aromatic hydrocarbons, including Benzo[a]pyrene (BaP), induce reproductive toxicity. Several existing studies have considered higher than environmentally relevant concentrations of BaP on male and female steroidogenesis following long-term exposure. Also, the impact of short-term exposure to BaP on gonadotropin-stimulated cells is understudied. Therefore, we evaluated the effect of 1 nM and 1 µM BaP on luteinizing hormone/choriogonadotropin (LH/hCG)-mediated signalling in two steroidogenic cell models, i.e. the mouse tumor Leydig cell line mLTC1, and the human primary granulosa lutein cells (hGLC) post 8- and 24-h exposure. Cell signalling studies were performed by homogeneous time-resolved fluorescence (HTRF) assay, bioluminescence energy transfer (BRET) and Western blotting, while immunostainings and immunoassays were used for intracellular protein expression and steroidogenesis analyses, respectively. BaP decreased cAMP production in gonadotropin-stimulated mLTC1 interfering with Gαs activation. Therefore, decrease in gonadotropin-mediated CREB phosphorylation in mLTC1 treated with 1 μM BaP was observed, while StAR protein levels in gonadotropin-stimulated mLTC1 cells were unaffected by BaP. Further, BaP decreased LH- and hCG-mediated progesterone production in mLTC1. Contrastingly, BaP failed to mediate any change in cAMP, genes and proteins of steroidogenic machinery and steroidogenesis of gonadotropin-treated hGLC. Our results indicate that short-term exposure to BaP significantly impairs steroidogenic signalling in mLTC1 interfering with Gαs. These findings could have a significant impact on our understanding of the mechanism of reproductive toxicity by endocrine disruptors., (© 2024. The Author(s).)

Bisphenol A (BPA) is a ubiquitous, synthetic chemical proven to induce reproductive disorders in both men and women. The available studies investigated the effects of BPA on male and female steroidogenesis following long-term exposure to the compound at relatively high environmental concentrations. However, the impact of short-term exposure to BPA on reproduction is poorly studied. We evaluated if 8 and 24 h exposure to 1 nM and 1 µM BPA perturbs luteinizing hormone/choriogonadotropin (LH/hCG)-mediated signalling in two steroidogenic cell models, i.e., the mouse tumour Leydig cell line mLTC1, and human primary granulosa lutein cells (hGLC). Cell signalling studies were performed using a homogeneous time-resolved fluorescence (HTRF) assay and Western blotting, while gene expression analysis was carried out using real-time PCR. Immunostainings and an immunoassay were used for intracellular protein expression and steroidogenesis analyses, respectively. The presence of BPA leads to no significant changes in gonadotropin-induced cAMP accumulation, alongside phosphorylation of downstream molecules, such as ERK1/2, CREB and p38 MAPK, in both the cell models. BPA did not impact STARD1 , CYP11A1 and CYP19A1 gene expression in hGLC, nor Stard1 and Cyp17a1 expression in mLTC1 treated with LH/hCG. Additionally, the StAR protein expression was unchanged upon exposure to BPA. Progesterone and oestradiol levels in the culture medium, measured by hGLC, as well as the testosterone and progesterone levels in the culture medium, measured by mLTC1, did not change in the presence of BPA combined with LH/hCG. These data suggest that short-term exposure to environmental concentrations of BPA does not compromise the LH/hCG-induced steroidogenic potential of either human granulosa or mouse Leydig cells.

We report the synthesis and pH dependent emission spectral behaviour of four emissive iridium(III) complexes (Ir1-Ir4) with two isomeric pairs of bis-trifluoromethyl appended benzimidazole ligands. The imidazolyl hydrogen(N-H) has been replaced by phenyl groups (N-Ph) in two ligands to understand the impact of hydrogen bonding on the photophysical properties of the complexes and it indeed plays interesting role in the charge-transfer dynamics. The pH dependent electronic spectral change is observed for two of the complexes. The enhancement of emission intensity is observed at different wavelength for pH<7 and pH>7 for Ir1 and Ir3. The emission sensing of biogenic amines with pk a values ranging from 5.80-9.74 is reported along with cellular imaging. The complex Ir1 specifically localizes within lysosome (pH=4.5-5) and thus image this organelle with great precision. The detail electronic spectra and electrochemical behaviour were reported here along with TDDFT results., (© 2024 Wiley-VCH GmbH.)