The effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin-releasing hormone neurons
<em><strong>Objective(s):</strong></em> Several pathological conditions are associated with hyper-production of testosterone; however, its impacts are not well understood. Hence, we evaluated the effects of supraphysiological levels of testosterone on gonadotropin-releasing h...
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| Format: | Article |
| Language: | English |
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Mashhad University of Medical Sciences
2019-09-01
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| Series: | Iranian Journal of Basic Medical Sciences |
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| Online Access: | http://ijbms.mums.ac.ir/article_13531_93f881cb5f55eaff89376e2bb0de07be.pdf |
| _version_ | 1818348890305331200 |
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| author | Mohammad Saied Salehi Homayoun Khazali Fariba Mahmoudi Mahyar Janahmadi |
| author_facet | Mohammad Saied Salehi Homayoun Khazali Fariba Mahmoudi Mahyar Janahmadi |
| author_sort | Mohammad Saied Salehi |
| collection | DOAJ |
| description | <em><strong>Objective(s):</strong></em> Several pathological conditions are associated with hyper-production of testosterone; however, its impacts are not well understood. Hence, we evaluated the effects of supraphysiological levels of testosterone on gonadotropin-releasing hormone (GnRH) system in the hypothalamus of male rats. Also, we assessed the expression of two excitatory (kisspeptin and neurokinin-B) and two inhibitory (dynorphin and RFamide-related-peptide) neuropeptides upstream of GnRH neurons as possible routes to relay androgen information. <br /><em><strong>Materials and Methods:</strong></em> Gonadectomized (GDX) male rats received single injection of 100, 250 or 500 mg/kg testosterone undecanoate and three weeks later, posterior (PH) and anterior (AH) hypothalamus was dissected for evaluation of target genes using quantitative RT-PCR.<br /><em><strong>Results:</strong></em> We found that GnRH mRNA in the PH was high in GDX rats and 500 mg/kg testosterone reduced GnRH level expression. Finding revealed extremely high level of Kiss1 mRNA in the PH of GDX rats. However, in GDX rats treated with different levels of testosterone, Kiss1 expression was not significantly different than control. We also found that testosterone replacement increased the Kiss1 mRNA level in the AH. Moreover, neurokinin-B mRNA level in PH of GDX rats was similar to control. However, excess testosterone levels were effective in significantly inducing the down-regulation of neurokinin-B expression. The basal level of dynorphin mRNA was increased following testosterone treatments in the AH, where we found no significant difference in the level of RFamide-related-peptide mRNA between the experimental groups. <br /><em><strong>Conclusion:</strong></em> Excess levels of testosterone could act differently from its physiological concentration to regulate hypothalamic androgen sensitive neurons to control GnRH cell. |
| first_indexed | 2024-12-13T17:57:14Z |
| format | Article |
| id | doaj.art-39628a1956cc4cdcbc8be051459ee905 |
| institution | Directory Open Access Journal |
| issn | 2008-3866 2008-3874 |
| language | English |
| last_indexed | 2024-12-13T17:57:14Z |
| publishDate | 2019-09-01 |
| publisher | Mashhad University of Medical Sciences |
| record_format | Article |
| series | Iranian Journal of Basic Medical Sciences |
| spelling | doaj.art-39628a1956cc4cdcbc8be051459ee9052022-12-21T23:36:19ZengMashhad University of Medical SciencesIranian Journal of Basic Medical Sciences2008-38662008-38742019-09-012291065107210.22038/ijbms.2019.36127.860513531The effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin-releasing hormone neuronsMohammad Saied Salehi0Homayoun Khazali1Fariba Mahmoudi2Mahyar Janahmadi3Clinical Neurology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran|Department of Animal Physiology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranDepartment of Animal Physiology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, IranFaculty of Basic Sciences, University of Mohaghegh Ardabili, Ardabil, IranNeuroscience Research Center and Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran<em><strong>Objective(s):</strong></em> Several pathological conditions are associated with hyper-production of testosterone; however, its impacts are not well understood. Hence, we evaluated the effects of supraphysiological levels of testosterone on gonadotropin-releasing hormone (GnRH) system in the hypothalamus of male rats. Also, we assessed the expression of two excitatory (kisspeptin and neurokinin-B) and two inhibitory (dynorphin and RFamide-related-peptide) neuropeptides upstream of GnRH neurons as possible routes to relay androgen information. <br /><em><strong>Materials and Methods:</strong></em> Gonadectomized (GDX) male rats received single injection of 100, 250 or 500 mg/kg testosterone undecanoate and three weeks later, posterior (PH) and anterior (AH) hypothalamus was dissected for evaluation of target genes using quantitative RT-PCR.<br /><em><strong>Results:</strong></em> We found that GnRH mRNA in the PH was high in GDX rats and 500 mg/kg testosterone reduced GnRH level expression. Finding revealed extremely high level of Kiss1 mRNA in the PH of GDX rats. However, in GDX rats treated with different levels of testosterone, Kiss1 expression was not significantly different than control. We also found that testosterone replacement increased the Kiss1 mRNA level in the AH. Moreover, neurokinin-B mRNA level in PH of GDX rats was similar to control. However, excess testosterone levels were effective in significantly inducing the down-regulation of neurokinin-B expression. The basal level of dynorphin mRNA was increased following testosterone treatments in the AH, where we found no significant difference in the level of RFamide-related-peptide mRNA between the experimental groups. <br /><em><strong>Conclusion:</strong></em> Excess levels of testosterone could act differently from its physiological concentration to regulate hypothalamic androgen sensitive neurons to control GnRH cell.http://ijbms.mums.ac.ir/article_13531_93f881cb5f55eaff89376e2bb0de07be.pdfGnRHKisspeptinNeurokinin BRFRPTestosterone |
| spellingShingle | Mohammad Saied Salehi Homayoun Khazali Fariba Mahmoudi Mahyar Janahmadi The effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin-releasing hormone neurons Iranian Journal of Basic Medical Sciences GnRH Kisspeptin Neurokinin B RFRP Testosterone |
| title | The effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin-releasing hormone neurons |
| title_full | The effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin-releasing hormone neurons |
| title_fullStr | The effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin-releasing hormone neurons |
| title_full_unstemmed | The effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin-releasing hormone neurons |
| title_short | The effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin-releasing hormone neurons |
| title_sort | effects of supraphysiological levels of testosterone on neural networks upstream of gonadotropin releasing hormone neurons |
| topic | GnRH Kisspeptin Neurokinin B RFRP Testosterone |
| url | http://ijbms.mums.ac.ir/article_13531_93f881cb5f55eaff89376e2bb0de07be.pdf |
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