Professor of Physiology
Dr. Fejes-Tóth received his D.M.D. degree at the Semmelweis University Medical School in Budapest, Hungary in 1972. He received post-doctoral training at the Department of Physiology at the same University. From 1973 to 1981 he was an Assistant Professor of Physiology. In 1982 he spent 1 year at the Department of Physiology at Dartmouth as Visiting Scientist. From 1983-85 he was a Visiting Professor at the Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, West Germany. Between 1985 and 1990 he worked in the Department of Medicine, at the Henry Ford Hospital, Detroit as a Senior Staff Investigator. He joined the Physiology Department at Dartmouth in 1990 and was promoted to Professor in 1995.
Typically, cell division results in two identical daughter cells. However, in a few cases division of the mother cell is asymmetric which results in daughter cells that differ biochemically and consequently have different fates. Such asymmetric cell divisions are especially important during embryonic development, and might be responsible for generating the diversity of cell types that characterizes complex multicellular organisms. In the fully developed organism replacement of dead cells is achieved either by simple duplication of the remaining cells or via differentiation of a precursor (stem) cell. The number of such stem cells is constant during adulthood suggesting that stem cells rejuvenate themselves through an asymmetric division. Observing such asymmetric cell divisions in somatic cells of higher organisms has proven to be more difficult than anticipated.
Recently a model system was developed in Dr. Fejes-Tóth's laboratory for studying asymmetric cell division in cultured renal collecting duct cells, which makes it possible to explore the mechanisms involved in this fundamental process. The main goal of a second project is to understand at the cellular and molecular level the mechanisms by which the renal collecting duct adapts to changes in acid/base balance. Depending on the acid/base status of the organism, the collecting duct either secretes or reabsorbs HCO3. HCO3 secretion and reabsorption take place in two subtypes of collecting duct cells, with opposing functional polarity. Ongoing studies are testing the hypothesis that adaptation to acidosis involves both up- and down-regulation of the transporters mediation these opposing functions as well as conversion of HCO3- secreting cells to HCO3 reabsorbing cells.
Fejes-Tóth, G., Náray-Fejes-Tóth A. Differentiation of renal ß-intercalated cells to aintercalated and principal cells in culture. Proc Natl Acad Sci USA 89:5487-5491, 1992.
Fejes-Tóth, G., W.R. Chen, E. Rusvai, T. Moser and A. Náray-Fejes-Tóth. Differential Expression of AE1 in Renal HCO3 Secreting and Reabsorbing Intercalated Cells. J. Biol. Chem., 269: 26717-26721, 1994.
Fejes-Tóth, G., E. Rusvai, K. Longo and A. Náray-Fejes-Tóth. Expression of the colonic H-K-ATPase mRNA in cortical collecting duct: Regulation by acid/base balance. Am. J. Physiol., 269: F551-F557, 1995.
Fejes-Tóth, G. and A. Náray-Fejes-Tóth. Effect of acid/base balance on H-ATPase 31 kD subunit mRNA levels in collecting cells. Kidney Int., 48:1420-1426, 1995.
Fejes-Tóth, G., D. Pearce, and A. Náray-Fejes-Tóth. Subcellular localization of mineralocorticoid receptors in living cells: Effects of agonists and antagonists. Proc. Natl. Acad. Sci. USA, 95:2973-2978, 1998.
Náray-Fejes-Tóth, A., C. Canessa, E.S. Cleaveland, G. Aldrich and G. Fejes-Tóth. Sgk is an aldosterone-induced kinase in the renal collecting duct: effects on epithelial Na channels. J. Biol. Chem, 274: 16973-16978, 1999.
Náray-Fejes-Tóth, A., and G. Fejes-Tóth. Sgk, an aldosterone-induced early-response gene in mineralocorticoid target cells, regulates epithelial sodium channel. Kidney Int., 57:1290-1294, 2000.
Náray-Fejes-Tóth, A., G. Fejes-Tóth, K.A. Volk and J.B. Stokes. SGK is a primary glucocorticoid-induced gene in human. J. Steroid Biochem. Mol. Biol. 75:51-56, 2000.
Fejes-Tóth, G. and A. Náray-Fejes-Tóth. Immunohistochemical localization of the colonic H,K-ATPase to the apical membrane of connecting tubule cells. Am. J. Pysiol, Renal, 281:F318-25, 2001.
Pearce D, Náray-Fejes-Toth A, and Fejes-Toth G. Determinants of subnuclear organization of mineralocorticoid receptor characterized through analysis wild type and mutant receptors. J Biol Chem. 277:1451-6. 2002.
Helms,M.N., G. Fejes-Tóth and A. Náray-Fejes-Tóth. Hormone-regulated transepithelial Na transport in mammalian CCD cells requires SGK1 expression. Am. J. Physiol, Renal,284:F480-F487, 2003.
Náray-Fejes-Tóth A, and Fejes-Tóth G. Physiology and gene expression by mineralocorticoids. Encycl. Hormones, in press, 2003.
Náray-Fejes-Tóth, A., M. N. Helms, J. B. Stokes and G. Fejes-Tóth. Regulation of sodium transport in mammalian collecting duct cells by aldosterone-induced kinase, SGK1: Structure/function studies. Mol. Cell. Endocrin. In press, 2003.