Distinguishing features of cytotoxic and pharmacological effects of selenite in murine mammary epithelial cells in vitro.
Previous studies have demonstrated that selenite exerts a reversible and non-lethal inhibition of cell growth which could be correlated with a 58 K selenoprotein. Prolonged exposure to 5 microM selenite is cytotoxic. This cytotoxic effect is heralded by the cells floating off the dish. These floating cells contained over a log more selenite than did the attached cells. The floating cells also had a higher total amount per cell of covalently incorporated selenite in the form of volatile selenides. No specific selenoprotein could be correlated with the cytotoxic effect of selenite. However, a greater aggregation of selenoproteins was observed in dead vs. viable cells. This change probably was a late manifestation of cell death, whereas the increased amount of volatile selenides marked the early stages of acute selenosis and cell death. The results suggest that the cellular response to selenite exposure contains two phases: an early reversible inhibition of cell growth, and a late irreversible cytotoxic effect. The former is characterized by an increase in a 58 K selenoprotein, whereas the latter by an increase in volatile selenides. The results suggest that experiments evaluating specific effects of selenite exposure on biochemical function need to distinguish between the two phases of cell response.
Morrison
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Department of Cell Biology, Baylor College of Medicine, Houston, TX 77030.
Medina
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D000818:Animals; D001345:Autoradiography; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D008321:Mammary Glands, Animal / Q000187:drug effects* / Q000473:pathology; D051379:Mice; D011506:Proteins / Q000032:analysis; D020887:Selenious Acid; D012643:Selenium / Q000494:pharmacology / Q000633:toxicity*; D051140:Selenoproteins; D014357:Trypsin
D011506:Proteins; D051140:Selenoproteins; D014357:Trypsin; D020887:Selenious Acid; D012643:Selenium