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Year : 2000  |  Volume : 32  |  Issue : 2  |  Page : 120--125

Inhibition of Ca 2+ -ATPase and perturbation in Ca ++ homeostasis in rat liver on administration of methyl isocyanate

K Jeevaratnam 
 

Correspondence Address:
K Jeevaratnam


Objectives: To study the perturbations of calcium homeostasis by methyl isocyanate (MIC), if any. Methods: Hepatic microsomal Ca2+ -ATPase activity, Ca2+ and 45Ca distribution in serum and hepatic subcellular fractions were determined. Results: Addition of MIC in vitro resulted in dose-dependent inhibition of Ca2+ -ATPase. Subcutaneous administration of MIC at lethal dose caused a significant inhibition of Ca2+ -ATPase activity in vivo and significant changes in subcellular Ca 2+ distribution in rat liver as a result of an enhanced extracellular Ca2+ influx. The serum Ca2+ level was decreased. There was an enhanced cytosolic Ca2+ which was accumulated primarily in the mitochondria. In these rats, there was a significant increase in the mitochondrial pool of reduced glutathione (GSH) with a concomitant decrease in the cytosolic GSH. The isolated hepatic mitochondria of these rats showed significantly lower rates of calcium-stimulated respiration. Conclusion: This study suggests that the perturbations in the intracellular calcium homeostasis due to inhibition of Ca2+ -ATPase by MIC in rat liver could be one of the several factors associated with its cytotoxicity.


How to cite this article:
Jeevaratnam K. Inhibition of Ca 2+ -ATPase and perturbation in Ca ++ homeostasis in rat liver on administration of methyl isocyanate.Indian J Pharmacol 2000;32:120-125


How to cite this URL:
Jeevaratnam K. Inhibition of Ca 2+ -ATPase and perturbation in Ca ++ homeostasis in rat liver on administration of methyl isocyanate. Indian J Pharmacol [serial online] 2000 [cited 2020 Aug 9 ];32:120-125
Available from: http://www.ijp-online.com/article.asp?issn=0253-7613;year=2000;volume=32;issue=2;spage=120;epage=125;aulast=Jeevaratnam;type=0