In vivo31P NMR studies of the hepatic response to l-ethionine in anesthetized rats

Abstract

Phosphorus-31 surface coil spectroscopy has been used to study the effects of l-ethionine administration on the hepatic metabolism of the anesthetized Sprague-Dawley rat. ATP levels were found to decrease by ∼30% 3 to 4 hr after administration of 1 mg/g body wt of l-ethionine to the anesthetized rat by gastric gavage. ATP levels returned to control values ∼8 hr postadministration. The relatively small decrease in ATP level was confirmed by extraction and conventional enzyme assay and is a consequence of the mode of administration of the ethionine. Hepatic inorganic phosphate levels rose concomitantly with the ATP fall. There were no significant changes in either cellular pH or Mg 2+ levels as monitored by the 31P shifts of sensitive metabolites. In vivo 31P NMR spectroscopy provides a promising approach to study the effects of hepatotoxicants on cellular ATP, pH, and Mg levels.