Effects of fenvalerate and esfenvalerate on hepatic gap junctional intercellular communication in rats

Effects of in vivo exposure with fenvalerate, esfenvalerate and DDT on hepatic gap junctional intercellular communication (GJIC) in Sprague-Dawley (SD) rats were examined by in vivo/in vitro dye-transfer assay and by immunohistochemical staining of connexin 32 (Cx32, major liver gap junction protein). Fenvalerate (75 mg/kg/day), esfenvalerate (25 mg/kg/day), DDT (50 mg/kg/day) and corn oil (vehicle control, 5 ml/kg/day) were administered orally once a day. Animals were killed at weeks 1, 2, 4 and 6 after starting the experiment. In the fenvalerate- and esfenvalerate-groups, no compound-related changes in GJIC and Cx32 expression were observed. On the contrary, in the DDT-group, average sizes of the dye spread after injection of Lucifer Yellow decreased at weeks 1, 2 and 4, and the area per GJ spot shown by Cx32-immunohistochemical staining decreased at weeks 4 and 6. It is concluded that neither fenvalerate nor esfenvalerate inhibits hepatic GJIC with in vivo exposure.