This program is aimed at the development and application of in vivo NMR spectroscopic methods for studying metabolism and its perturbation by chemical toxins. The two primary applications during the past year were: (1) measurements or oxygen levels in the vitreous compartment of the rabbit eye, and its perturbation by various agents, and (2) studies of the effects of boric acid on the carbohydrate metabolism of Sertoli cells. In the first series of studies, oxygen levels have been determined based on the concentration-dependent perturbation of the spin lattice relaxation rate of perfluorotributyl amine. This approach requires that either all or a portion of the vitreous humor be replaced by the perfluorocarbon. Two types of measurement were carried out, one in which the vitreous was entirely replaced, and a second in which small, 5 um spheres of perfluorocarbon were placed in the eye. Effects of damage to the blood- retinal barrier on the oxygen level of the vitreous were quantified, and a protective effect of steroids was demonstrated. A second series of studies is aimed at understanding the physiological effects of boric and boronic acids, and the potential basis for the toxic effects of these compounds which have been reported. Although boron is an essential element for plants, no need in animal systems has been established. Recently it has been demonstrated that at relatively high levels boric acid is selectively toxic to the male reproductive system. NMR studies of the effects of boric acid on the metabolism of sertoli cell cultures have been carried out using carbon-13 labeled glucose. An initial series of measurements indicates that the glutamine/glutamate ratio is significantly reduced in cells exposed to boric acid.

Agency
National Institute of Health (NIH)
Institute
National Institute of Environmental Health Sciences (NIEHS)
Type
Intramural Research (Z01)
Project #
1Z01ES050110-04
Application #
3841104
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
4
Fiscal Year
1992
Total Cost
Indirect Cost
City
State
Country
United States
Zip Code
Bonini, Marcelo G; Gabel, Scott A; Ranguelova, Kalina et al. (2009) Direct magnetic resonance evidence for peroxymonocarbonate involvement in the cu,zn-superoxide dismutase peroxidase catalytic cycle. J Biol Chem 284:14618-27
Gabel, Scott A; London, Robert E (2008) Ternary borate-nucleoside complex stabilization by ribonuclease A demonstrates phosphate mimicry. J Biol Inorg Chem 13:207-17
Yoshioka, Jun; Imahashi, Kenichi; Gabel, Scott A et al. (2007) Targeted deletion of thioredoxin-interacting protein regulates cardiac dysfunction in response to pressure overload. Circ Res 101:1328-38
Transue, Thomas R; Gabel, Scott A; London, Robert E (2006) NMR and crystallographic characterization of adventitious borate binding by trypsin. Bioconjug Chem 17:300-8
Gabel, Scott A; Walker, Vickie R; London, Robert E et al. (2005) Estrogen receptor beta mediates gender differences in ischemia/reperfusion injury. J Mol Cell Cardiol 38:289-97
Imahashi, Kenichi; London, Robert E; Steenbergen, Charles et al. (2004) Male/female differences in intracellular Na+ regulation during ischemia/reperfusion in mouse heart. J Mol Cell Cardiol 37:747-53
Transue, Thomas R; Krahn, Joseph M; Gabel, Scott A et al. (2004) X-ray and NMR characterization of covalent complexes of trypsin, borate, and alcohols. Biochemistry 43:2829-39
Gao, Guanghua; Prutzman, Kirk C; King, Michelle L et al. (2004) NMR solution structure of the focal adhesion targeting domain of focal adhesion kinase in complex with a paxillin LD peptide: evidence for a two-site binding model. J Biol Chem 279:8441-51
Chen, Jarvis; Petranka, John; Yamamura, Ken et al. (2003) Gender differences in sarcoplasmic reticulum calcium loading after isoproterenol. Am J Physiol Heart Circ Physiol 285:H2657-62
London, Robert E; Gabel, Scott A (2002) Formation of a trypsin-borate-4-aminobutanol ternary complex. Biochemistry 41:5963-7

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