CYP1B1 is unique among P450 cytochromes in exhibiting inductive responses mediated by both the Ah receptor (AhR) and cAMP. cAMP induction was mediated either by a 189bp far upstream enhancer region (FUER, -5110 to -5298) or by a 230bp AhR-responsive enhancer region (AhER) (-797 to -1026). CYP1B1 luciferase reporters respond selectively to cAMP and TCDD in adrenal Y-1 cells (only cAMP), testis MA10 cells (cAMP>TCDD), and C3H10T1/2 mouse embryo fibroblasts (only TCDD). In Y-1 cells, which lack AhR, cAMP induction is totally dependent on the FUER, including absolute requirements for upstream and downstream halves of this region, and for CREB activity at a CRE sequence located at the 3(')-end. cAMP stimulation of the FUER was remarkably high (27-fold) and equally effective when linked to an HSV-TK promoter, indicating direct cAMP activation of the FUER. Binding of CREB to the essential CRE was demonstrated along with dominant negative effects of functionally impaired mutants. cAMP induction in MA10 cells was partially mediated by the FUER mechanism but was regulated additionally by AhER through AhR activity. MA10 cells also exhibit cAMP-dependent AhR down-regulation and AhR/Arnt complex formation. Mutations in AhER including XRE5 were similarly inhibitory to cAMP stimulation in MA10 cells and to TCDD stimulation in C3H10T1/2 cells. Transfection of AhR into the AhR-deficient Y-1 cells did not introduce this second mechanism, which indicated a need for additional components that are present in MA10 cells.
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http://dx.doi.org/10.1016/s0003-9861(03)00282-0 | DOI Listing |
Biol Reprod
November 2024
Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada.
Bisphenols are a family of chemicals used in the manufacture of consumer products containing polycarbonate plastics and epoxy resins. Studies have shown that exposure to bisphenol A (BPA) may disrupt steroidogenesis and induce adverse effects on male and female reproduction, but little is known about BPA replacements. We determined the effects of six bisphenols on the steroidogenic function of MA-10 Leydig cells and KGN granulosa cells by measuring the levels of progesterone and estradiol produced by these cells as well as the expression of transcripts involved in steroid and cholesterol biosynthesis.
View Article and Find Full Text PDFCancer Genomics Proteomics
October 2024
Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan, R.O.C.
Background/aim: Fibroblast growth factor 9 (FGF9) is a member of the human FGF family known for its pivotal roles in various biological processes, such as cell proliferation, tissue repair, and male sex determination including testis formation. Cordycepin, a bioactive compound found in Cordyceps sinensis, exhibits potent antitumor effects by triggering apoptosis and/or autophagy pathways. Our research has unveiled that FGF9 promotes proliferation and tumorigenesis in MA-10 mouse Leydig tumor cells, as the phenomena are effectively countered by cordycepin through apoptosis induction.
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January 2025
Department of Urology, Yamaguchi University School of Medicine, Ube, Japan.
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September 2024
109 Greene Hall, Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
Leydig cells (LCs) in the testes produce the male sex hormone testosterone (T). Several xenobiotics, including clinical drugs, supplements, and environmental chemicals, are known to disrupt T homeostasis. Notably, some of these xenobiotics are known to activate the pregnane X receptor (PXR), a ligand-dependent nuclear receptor.
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December 2024
Biology Department, Université de Moncton, Moncton, New Brunswick, Canada, E1A 3E9. Electronic address:
Leydig cells are the main testosterone-producing cells in males. During androgen synthesis, cholesterol enters the mitochondria via the STAR protein and is converted into pregnenolone by the CYP11A1 enzyme. This steroid is then exported from the mitochondria to be metabolized to progesterone by the HSD3B1 enzyme in the endoplasmic reticulum.
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