title: Inhibition of cortisol secretion in dispersed head kidney cells of rainbow trout (Oncorhynchus mykiss) by endosulfan, an organochlorine pesticide.
abstract: The effects of endosulfan, an organochlorine pesticide, on cortisol secretion in vitro were investigated in enzymatically dispersed head kidney cells of rainbow trout, Oncorhynchus mykiss. First, the conditions for maximal cortisol secretion were characterized by selecting the optimal concentrations of adrenocorticotropin (ACTH) (1 IU/ml) and N(6), 2'-o-dibutyryladenosine 3':5'-cyclic monophosphate (dbcAMP) (2 mM), incubation temperature (15 degrees ) and time period (60 min for ACTH, 120 min for dbcAMP), number of cells per incubation well (75 x 10(6)/ml), and osmolarity of the medium (270 mosmol/L). Exposure of head kidney cells to endosulfan decreased ACTH- or dbcAMP-stimulated cortisol secretion and cell viability in a concentration-dependent pattern and the doses required to disrupt cortisol secretion were significantly lower than doses lethal to the head kidney cells. The median effective concentration of endosulfan (EC(50), the dose that inhibits cortisol secretion by 50%) was 17.3 microM while the median lethal concentration (LC(50), the dose that kills 50% of the cells) was 308 microM. Our study identified endosulfan as an environmental endocrine disrupting chemical that interferes with the normal secretory function of teleost interrenal steroidogenic cells. Multiple sites may be affected within the steroidogenic cells since dbcAMP could not restore cortisol secretion in endosulfan exposed cells.
authors.affiliation: Département des Sciences biologiques and TOXEN Research Centre, Université du Québec à Montréal, Montréal, Québec, H3C 3P8, Canada.
authors.forename: V S
authors.initials: VS
authors.lastname: Leblond
authors.forename: M
authors.initials: M
authors.lastname: Bisson
authors.forename: A
authors.initials: A
authors.lastname: Hontela
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D004726:Endosulfan / Q000494:pharmacology*; D006843:Hydrocarbons, Chlorinated; D006854:Hydrocortisone / Q000378:metabolism*; D007306:Insecticides / Q000494:pharmacology*; D007668:Kidney / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D009994:Osmolar Concentration; D013696:Temperature
chemical_list: D006843:Hydrocarbons, Chlorinated; D007306:Insecticides; D003994:Bucladesine; D000324:Adrenocorticotropic Hormone; D004726:Endosulfan; D006854:Hydrocortisone