Biphasic lindane-induced oxidation of glutathione and inhibition of gap junctions in myometrial cells.
The insecticide lindane (gamma-hexachlorocyclohexane) inhibits gap junction intercellular communication in rat myometrial cells by a mechanism involving oxidative stress. We hypothesized that oxidation of reduced glutathione (GSH) to glutathione disulfide (GSSG) and subsequent S-glutathionylation provide a mechanistic link between lindane-induced oxidative stress and lindane's inhibition of myometrial gap junction communication. Gap junction communication between cultured rat myometrial myocytes was assessed by Lucifer yellow dye transfer after microinjection. A biphasic pattern was confirmed, with dye transfer nearly abolished after 1 h of exposure to 100 microM lindane followed initially by recovery after lindane removal, and then the development 4 h after termination of lindane exposure of a delayed-onset, sustained inhibition that continued for 96 h. As measured by HPLC, cellular GSH varied over a 24-h period in a biphasic fashion that paralleled lindane-induced inhibition of dye transfer, whereas GSSG levels increased in a manner inversely related to GSH. In accordance, GSH/GSSG ratios were depressed at times when GSH and dye transfer were low. Lindane substantially increased S-glutathionylation in a concentration-dependent manner, measured biochemically by GSSG reductase-stimulated release of GSH from precipitated proteins. Furthermore, treatments that promoted accumulation of GSSG (50 microM diamide and 25 microM 1,3-bis(2-chloroethyl)-1-nitrosourea [BCNU]) inhibited Lucifer yellow dye transfer between myometrial cells. Findings that lindane induced GSH oxidation to GSSG with increased S-glutathionylation, together with the diamide and BCNU results, suggest that oxidation of GSH to GSSG is a component of the mechanism by which lindane inhibits myometrial gap junctions.
Caruso
Rita Loch
RL
Toxicology Program, Department of Environmental Health, University of Michigan, 1420 Washington Heights, Ann Arbor, Michigan 48109-2029, USA. rlc@umich.edu
Upham
Brad L
BL
Harris
Craig
C
Trosko
James E
JE
D000818:Animals; D002330:Carmustine / Q000494:pharmacology; D002450:Cell Communication / Q000187:drug effects*; D002478:Cells, Cultured; D003958:Diamide / Q000494:pharmacology; D005260:Female; D005456:Fluorescent Dyes / Q000378:metabolism; D017629:Gap Junctions / Q000187:drug effects* / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D019803:Glutathione Disulfide / Q000378:metabolism; D001556:Hexachlorocyclohexane / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007546:Isoquinolines / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism; D009215:Myometrium / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley
D005456:Fluorescent Dyes; D007306:Insecticides; D007546:Isoquinolines; D003958:Diamide; D001556:Hexachlorocyclohexane; C017475:lucifer yellow; D005978:Glutathione; D002330:Carmustine; D019803:Glutathione Disulfide