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 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 hours. 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.

Retracted: Effects of Di‐isononyl Phthalate on Neuropeptide Y Expression in Differentiating Human Neuronal Cells

“…The difference in the dose-response patterns between DiNP and MiNP might reflect differences in their physico-chemical characteristics such as lipophilicity, with DiNP being more lipophilic than MiNP making it more cell membrane permeable. Lipophilicity (log K ow ) has been shown to predict phthalate partitioning between media and cell lysate fractions [28]. Judging from our present data, it is not clear whether the parent compound DiNP does attenuate NPY mRNA expression by itself or via its metabolite MiNP.…”

Phthalate side-chain structures and hydrolysis metabolism associated with steroidogenic effects in MLTC-1 Leydig cells

“…It is well-documented that phthalate diesters can be quickly hydrolysed into monoesters in mammals by some non-specific esterases and lipases in the intestines protecting their ester bonds, resulting in poor bioavailability. The molecular specific hydrolysis agrees with in vitro liver microsomes tests and an in vivo kinetics study (Hanioka et al 2012;Harris et al 2016). In addition, the hydrolysis rates to high-dose diesters (100 μM) are lower than to low-dose (10 μM), so it is suspected that the process is not inducible; this is inconsistent with this notion that CAR regulation is constitutive but inducible.…”

“…Then these metabolites are phase II conjugated before they are excreted via the urine (Calafat et al 2006;Frederiksen et al 2007). Esterases involved in phthalates' phase I hydrolysis can be found in the small intestine, colon, kidney, liver, heart brain and testis (Harris et al 2016;Xu et al 2002).…”

Toxicity of Cosmetic Products: Endocrine Disruptor Chemicals

“…[33][34][35][36] Metabolik sendromlar üzerine yapılan çalışmalarda; sıçan testiküler hücrelerinde lipit metabolizması, inflamatuar yanıt, erkek üreme sistemi gelişiminde rol oynayan genlerde değişikliğe neden olabileceği; insan pankreatik β hücrelerinde de proliferasyonu tetiklediği, maruziyetleri sonucu bu hücrelerdeki insülin içeriğinin yükseldiği, bu sebeple Tip 2 diyabetle ilişkili olabileceği düşünülmektedir. 37,38 Ftalat maruziyetiyle düşük sperm kalitesi, sperm DNA bütünlüğünde bozulma, cinsiyet ve tiroid hormonları konsantrasyonlarının düşmesi, obezite, meme kanseri ve erken puberte arasındaki ilişkiler aydınlatılmaya çalışılmıştır. 35,[39][40][41][42] Avrupa Birliği ülkelerinde kozmetik ürünlerde kullanımı yasaklanmıştır.…”