Inhibition of hepatocyte gap junctional communication by 25-hydroxycholesterol may be mediated through free radicals.
25-Hydroxycholesterol, an autoxidation product of cholesterol, has been shown to inhibit gap junctional communication between rat hepatocytes. In this study, we investigated whether free radicals are responsible for the effect of 25-hydroxycholesterol on hepatocytes. Addition of superoxide dismutase, hydroxyl radical scavenger mannitol, or the antioxidants diphenylphenylenediamine and alpha-tocopherol markedly decreased the inhibitory effect of 25-hydroxycholesterol. However, addition of catalase or the catalase inhibitor aminotriazole did not influence the inhibition of gap junctional communication by 25-hydroxycholesterol. Data from this study suggest that free radicals other than hydrogen peroxide are involved in the mechanism of 25-hydroxycholesterol-induced inhibition of gap junctional communication.
Guo
X
X
Division of Pharmacology, National Institute of Hygienic Sciences, Tokyo, Japan.
Ohno
Y
Y
Takanaka
A
A
D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002450:Cell Communication / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004347:Drug Interactions; D005609:Free Radicals / Q000494:pharmacology; D017629:Gap Junctions / Q000187:drug effects*; D006888:Hydroxycholesterols / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D008099:Liver / Q000166:cytology / Q000187:drug effects*; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D010655:Phenylenediamines / Q000494:pharmacology; D011335:Proadifen / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000494:pharmacology; D014810:Vitamin E / Q000494:pharmacology
D000975:Antioxidants; D005609:Free Radicals; D006888:Hydroxycholesterols; D010655:Phenylenediamines; D014810:Vitamin E; D008353:Mannitol; C007997:25-hydroxycholesterol; D011335:Proadifen; C004845:N,N'-diphenyl-4-phenylenediamine; D013482:Superoxide Dismutase