Glutathione plays a central role in cellular defense against reactive electrophiles and oxidants, two of the most common producers of cellular injury in both chemical toxicity and disease. Our overall objective is to identify mechanisms for disposition of glutathione S conjugates and mercapturic acids (S-substituted N-acetyl-L-cysteines) via a novel intrahepatic pathway. This pathway was recently described from our laboratory, and is thought to play an important role in hepatic detoxification of electrophiles and toxic metals such as mercury, mercapturic acid biosynthesis, bile formation, and glutathione homeostasis.
The specific aims are: (1) Define the role of the intrahepatic gamma- glutamyl cycle in mercapturic acid formation. In contrast to current models of mercapturic acid biosynthesis, our recent studies demonstrated that this detoxification pathway can occur entirely within the liver. Moreover, in contrast to current thinking, a representative mercapturic acid (S.2,4-dinitrophenyl-N-acetylcysteine, or DNP-NAC) was excreted by isolated rat liver almost exclusively into bile, and not into the sinusoidal circulation. To best this model and to identify the mechanisms involved, we plan to: A.- Examine sinusoidal uptake and disposition of structurally distinct cysteine S-conjugates and mercapturic acids, both in vivo and in the perfused liver (with ethyl iodide and 1-chloro-2,4-dinitrobenzene as model xenobiotics). B. Using isolated canalicular and basolateral membrane vesicles, define the driving forces and substrate specificities for hepatic transport of mercapturic acids, and C. Test the role of sinusoidal gamma-glutamyl transferase iii hepatic clearance of GSH and glutathione S-conjugates, and in mercapturic acid biosynthesis. (2) Express the novel canalicular ATP-independent, high affinity glutathione S-conjugate carrier in Xenopus laevis oocytes using poly(A)+ RNA isolated from rat liver, and characterize the properties of the transporter in the oocyte system. With oocytes as a functional assay for transport, use expression cloning strategy to identify the cDNA for the transporter. Cloning will not only yield important structural information on this glutathione S-conjugate transporter, but will allow production of molecular probes with which to define its role in xenobiotic metabolism in liver and the whole organism. It is anticipated that these studies will ultimately provide information critical for the prevention and treatment of toxic liver cell injury and its extrahepatic complications induced by reactive electrophilic compounds.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Project (R01)
Project #
Application #
Study Section
Toxicology Subcommittee 2 (TOX)
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Rochester
Public Health & Prev Medicine
Schools of Dentistry
United States
Zip Code
García, Marta; González de Buitrago, Jesús; Jiménez-Rosés, Mireia et al. (2017) Central Hypothyroidism Due to a TRHR Mutation Causing Impaired Ligand Affinity and Transactivation of Gq. J Clin Endocrinol Metab 102:2433-2442
Christian, Whitney V; Li, Na; Hinkle, Patricia M et al. (2012) ?-Subunit of the Ost?-Ost? organic solute transporter is required not only for heterodimerization and trafficking but also for function. J Biol Chem 287:21233-43
Krance, Suzanne M; Keng, Peter C; Palis, James et al. (2010) Transient glutathione depletion determines terminal differentiation in HL-60 cells. Oxid Med Cell Longev 3:53-60
Shi, Shujie; Notenboom, Sylvia; Dumont, Mark E et al. (2010) Identification of human gene products containing Pro-Pro-x-Tyr (PY) motifs that enhance glutathione and endocytotic marker uptake in yeast. Cell Physiol Biochem 25:293-306
Ballatori, Nazzareno; Li, Na; Fang, Fang et al. (2009) OST alpha-OST beta: a key membrane transporter of bile acids and conjugated steroids. Front Biosci (Landmark Ed) 14:2829-44
Ballatori, Nazzareno; Krance, Suzanne M; Marchan, Rosemarie et al. (2009) Plasma membrane glutathione transporters and their roles in cell physiology and pathophysiology. Mol Aspects Med 30:13-28
Madejczyk, Michael S; Boyer, James L; Ballatori, Nazzareno (2009) Hepatic uptake and biliary excretion of manganese in the little skate, Leucoraja erinacea. Comp Biochem Physiol C Toxicol Pharmacol 149:566-71
Ballatori, Nazzareno; Krance, Suzanne M; Notenboom, Sylvia et al. (2009) Glutathione dysregulation and the etiology and progression of human diseases. Biol Chem 390:191-214
Ballatori, Nazzareno; Fang, Fang; Christian, Whitney V et al. (2008) Ostalpha-Ostbeta is required for bile acid and conjugated steroid disposition in the intestine, kidney, and liver. Am J Physiol Gastrointest Liver Physiol 295:G179-G186
Marchan, Rosemarie; Hammond, Christine L; Ballatori, Nazzareno (2008) Multidrug resistance-associated protein 1 as a major mediator of basal and apoptotic glutathione release. Biochim Biophys Acta 1778:2413-20

Showing the most recent 10 out of 54 publications