title: Phthalate metabolism and kinetics in an in vitro model of testis development.
abstract: We have developed an in vitro model of testis development (3D-TCS) using rat testicular cells overlaid with extracellular matrix. One barrier preventing utilization of in vitro models in toxicity testing is the absence of metabolic capability. Another challenge is lack of kinetic data for compounds in vitro. We characterized metabolic capabilities and investigated the kinetics of phthalate male reproductive toxicants in the 3D-TCS. Cells were treated with three phthalate diesters for 2, 8 and 24 h. Parent compounds and metabolites were measured in cell culture media and cell lysate via mass spectrometry. Levels of monoester metabolites were used as an indication of metabolism of phthalates via lipase activity. Metabolites were detected in all treated cell media and cell lysate samples, with levels ranging from <0.5-14.7% of initial mass of parent compound. Phthalates partitioned between media and lysate in a manner consistent with each compound's degree of lipophilicity. UDGPT activity was detected in DBP and DEP treated samples. 3D-TCS microarray data indicated gene expression for lipases and CYPP450s. Results indicate that the 3D-TCS is a metabolically active co-culture and that physiochemical properties can provide information about the kinetics of compounds in the 3D-TCS, improving our ability to interpret results from the model.
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, United States.
authors.forename: Sean
authors.initials: S
authors.lastname: Harris
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, United States.
authors.forename: Susanna
authors.initials: S
authors.lastname: Wegner
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, United States; Institute for Risk Analysis and Risk Communication, University of Washington, Seattle, WA 98105, United States.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Hong
authors.affiliation: Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, United States; Institute for Risk Analysis and Risk Communication, University of Washington, Seattle, WA 98105, United States. Electronic address: faustman@u.washington.edu.
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Faustman
mesh_terms: D020003:1-Octanol / Q000737:chemistry; D000818:Animals; D018920:Coculture Techniques; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D015870:Gene Expression; D014453:Glucuronosyltransferase / Q000378:metabolism; D007700:Kinetics; D008049:Lipase / Q000235:genetics / Q000378:metabolism; D008297:Male; D010795:Phthalic Acids / Q000737:chemistry / Q000494:pharmacology*; D017207:Rats, Sprague-Dawley; D013737:Testis / Q000254:growth & development / Q000378:metabolism*; D014867:Water / Q000737:chemistry
chemical_list: D010795:Phthalic Acids; D014867:Water; D003577:Cytochrome P-450 Enzyme System; D014453:Glucuronosyltransferase; D008049:Lipase; D020003:1-Octanol
keywords: Metabolism; Organotypic; Phthalate esters; Reproductive toxicity; Testes; in vitro models