title: Further analysis of behavioral and endocrine consequences of chronic exposure of male Wistar rats to subtoxic doses of endocrine disruptor chlorobenzenes.
abstract: Many chemicals utilized by humans are present as environmental pollutants and may influence homeostasis from neurological, immunological, endocrinological and/or behavioral aspects. Such agents, acting alone or in ambient mixtures, may be biologically active even at extremely low doses, and it may be postulated that stable, bioaccumulative, reactive endocrine disruptors may affect central and/or peripheral secretion of arginine-vasopressin (AVP) and oxytocin (OXT) and thereby related physiological and behavioral functions, potentially leading to disorders in exposed subjects. The primary aim of this study was to demonstrate effects of chronic exposure to a low dose of an orally administered chlorobenzene mixture on anxiety-related and aggressive behavior mediated largely by AVP and OXT. Chlorobenzenes were applied to model ambient mixtures of endocrine disruptors. Adult, male Wistar rats were exposed daily to 0.1 μg/kg of 1,2,4-trichlorobenzene and hexachlorobenzene via a stomach tube for 30, 60 or 90 days, after which anxiety-related and aggressive behavioral elements were examined in open-field, elevated plus maze and resident-intruder tests. The plasma levels of AVP, OXT and adrenocorticotrophic hormone at the endpoints were measured by radioimmunoassay or immunochemiluminescence assay. The levels of basal and serotonin- or norepinephrine-stimulated AVP and OXT secretion in pituicyte cultures prepared from the posterior lobe of the pituitaries were also measured. The hormone levels proved to be increased to extents depending on the duration of exposure to the chlorobenzenes. Several anxiety-related and aggressive behavioral elements were also enhanced following chlorobenzene exposure, while certain explorative and locomotive elements of the animals were decreased. As both physiological and behavioral elements were modulated by chronic, subtoxic doses of chlorobenzenes, it is concluded that doses of such environmental pollutants low enough to fall outside the range of legal regulation may pose potential risks of anxiogenic and/or aggressive consequences in exposed subjects, including humans.
authors.affiliation: Endocrine Unit of First Department of Internal Medicine, Faculty of Medicine, University of Szeged, Korányi fasor 8-10, H-6720, Szeged, Hungary. valkusz@endoc.szote.u-szeged.hu
authors.forename: Z
authors.initials: Z
authors.lastname: Valkusz
authors.forename: G
authors.initials: G
authors.lastname: Nagyéri
authors.forename: M
authors.initials: M
authors.lastname: Radács
authors.forename: T
authors.initials: T
authors.lastname: Ocskó
authors.forename: P
authors.initials: P
authors.lastname: Hausinger
authors.forename: M
authors.initials: M
authors.lastname: László
authors.forename: F A
authors.initials: FA
authors.lastname: László
authors.forename: A
authors.initials: A
authors.lastname: Juhász
authors.forename: J
authors.initials: J
authors.lastname: Julesz
authors.forename: R
authors.initials: R
authors.lastname: Pálföldi
authors.forename: M
authors.initials: M
authors.lastname: Gálfi
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000374:Aggression / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001007:Anxiety / Q000139:chemically induced* / Q000523:psychology; D001127:Arginine Vasopressin / Q000097:blood / Q000378:metabolism*; D002478:Cells, Cultured; D002722:Chlorobenzenes / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D004785:Environmental Pollutants / Q000008:administration & dosage / Q000494:pharmacology; D006581:Hexachlorobenzene / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009638:Norepinephrine / Q000494:pharmacology; D010121:Oxytocin / Q000097:blood / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology
chemical_list: D002722:Chlorobenzenes; D004785:Environmental Pollutants; D001127:Arginine Vasopressin; C036720:trichlorobenzene; D012701:Serotonin; D006581:Hexachlorobenzene; D010121:Oxytocin; D000324:Adrenocorticotropic Hormone; D009638:Norepinephrine