title: Delayed Neuroendocrine Sexual Maturation in Female Rats After a Very Low Dose of Bisphenol A Through Altered GABAergic Neurotransmission and Opposing Effects of a High Dose.
abstract: Rat sexual maturation is preceded by a reduction of the interpulse interval (IPI) of GnRH neurosecretion. This work aims at studying disruption of that neuroendocrine event in females after early exposure to a very low dose of bisphenol A (BPA), a ubiquitous endocrine disrupting chemical. Female rats were exposed to vehicle or BPA 25 ng/kg·d, 25 μg/kg·d, or 5 mg/kg·d from postnatal day (PND)1 to PND5 or PND15. Exposure to 25 ng/kg·d of BPA for 5 or 15 days was followed by a delay in developmental reduction of GnRH IPI studied ex vivo on PND20. After 15 days of exposure to that low dose of BPA, vaginal opening tended to be delayed. In contrast, exposure to BPA 5 mg/kg·d for 15 days resulted in a premature reduction in GnRH IPI and a trend toward early vaginal opening. RNA sequencing analysis on PND20 indicated that exposure to BPA resulted in opposing dose effects on the mRNA expression of hypothalamic genes involved in gamma aminobutyric acid A (GABAA) neurotransmission. The study of GnRH secretion in vitro in the presence of GABAA receptor agonist/antagonist confirmed an increased or a reduced GABAergic tone after in vivo exposure to the very low or the high dose of BPA, respectively. Overall, we show for the first time that neonatal exposure to BPA leads to opposing dose-dependent effects on the neuroendocrine control of puberty in the female rat. A very low and environmentally relevant dose of BPA delays neuroendocrine maturation related to puberty through increased inhibitory GABAergic neurotransmission.
authors.affiliation: Neuroendocrinology Unit (D.F., A.G., J.-P.B., A.-S.P.), Interdisciplinary Cluster for Applied Genoproteomics Neurosciences; Interdisciplinary Cluster for Applied Genoproteomics Transcriptomic Platform (B.H.); and Department of Public Health (A.-F.D.), Biostatistics Unit, University of Liège, Sart-Tilman, B-4000 Liège, Belgium; and Department of Pediatrics (A.G., J.-P.B., A.-S.P.), Centre Hospitalier Universitaire de Liège, B-4032 Chênée, Belgium.
authors.forename: Delphine
authors.initials: D
authors.lastname: Franssen
authors.affiliation: Neuroendocrinology Unit (D.F., A.G., J.-P.B., A.-S.P.), Interdisciplinary Cluster for Applied Genoproteomics Neurosciences; Interdisciplinary Cluster for Applied Genoproteomics Transcriptomic Platform (B.H.); and Department of Public Health (A.-F.D.), Biostatistics Unit, University of Liège, Sart-Tilman, B-4000 Liège, Belgium; and Department of Pediatrics (A.G., J.-P.B., A.-S.P.), Centre Hospitalier Universitaire de Liège, B-4032 Chênée, Belgium.
authors.forename: Arlette
authors.initials: A
authors.lastname: Gérard
authors.affiliation: Neuroendocrinology Unit (D.F., A.G., J.-P.B., A.-S.P.), Interdisciplinary Cluster for Applied Genoproteomics Neurosciences; Interdisciplinary Cluster for Applied Genoproteomics Transcriptomic Platform (B.H.); and Department of Public Health (A.-F.D.), Biostatistics Unit, University of Liège, Sart-Tilman, B-4000 Liège, Belgium; and Department of Pediatrics (A.G., J.-P.B., A.-S.P.), Centre Hospitalier Universitaire de Liège, B-4032 Chênée, Belgium.
authors.forename: Benoit
authors.initials: B
authors.lastname: Hennuy
authors.affiliation: Neuroendocrinology Unit (D.F., A.G., J.-P.B., A.-S.P.), Interdisciplinary Cluster for Applied Genoproteomics Neurosciences; Interdisciplinary Cluster for Applied Genoproteomics Transcriptomic Platform (B.H.); and Department of Public Health (A.-F.D.), Biostatistics Unit, University of Liège, Sart-Tilman, B-4000 Liège, Belgium; and Department of Pediatrics (A.G., J.-P.B., A.-S.P.), Centre Hospitalier Universitaire de Liège, B-4032 Chênée, Belgium.
authors.forename: Anne-Françoise
authors.initials: AF
authors.lastname: Donneau
authors.affiliation: Neuroendocrinology Unit (D.F., A.G., J.-P.B., A.-S.P.), Interdisciplinary Cluster for Applied Genoproteomics Neurosciences; Interdisciplinary Cluster for Applied Genoproteomics Transcriptomic Platform (B.H.); and Department of Public Health (A.-F.D.), Biostatistics Unit, University of Liège, Sart-Tilman, B-4000 Liège, Belgium; and Department of Pediatrics (A.G., J.-P.B., A.-S.P.), Centre Hospitalier Universitaire de Liège, B-4032 Chênée, Belgium.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bourguignon
authors.affiliation: Neuroendocrinology Unit (D.F., A.G., J.-P.B., A.-S.P.), Interdisciplinary Cluster for Applied Genoproteomics Neurosciences; Interdisciplinary Cluster for Applied Genoproteomics Transcriptomic Platform (B.H.); and Department of Public Health (A.-F.D.), Biostatistics Unit, University of Liège, Sart-Tilman, B-4000 Liège, Belgium; and Department of Pediatrics (A.G., J.-P.B., A.-S.P.), Centre Hospitalier Universitaire de Liège, B-4032 Chênée, Belgium.
authors.forename: Anne-Simone
authors.initials: AS
authors.lastname: Parent
mesh_terms: D000818:Animals; D001559:Benzhydryl Compounds / Q000008:administration & dosage*; D001640:Bicuculline / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D052244:Endocrine Disruptors / Q000008:administration & dosage*; D004968:Estrogens, Non-Steroidal / Q000008:administration & dosage*; D005260:Female; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D059330:GABAergic Neurons / Q000187:drug effects* / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D009118:Muscimol / Q000494:pharmacology; D010636:Phenols / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D012741:Sexual Maturation / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D001640:Bicuculline; D052244:Endocrine Disruptors; D004968:Estrogens, Non-Steroidal; D058785:GABA-A Receptor Agonists; D058787:GABA-A Receptor Antagonists; D007987:Gonadotropin-Releasing Hormone; D009118:Muscimol; D010636:Phenols; C006780:bisphenol A; D000098826:Bisphenol A Compounds