Studies on the hexose monophosphate shunt (HMPS) and its associated pathways are proposed in this application. We will examine the following five topics: 1) Control of the HMPS; 2) Activity of the HMPS and its associated pathways; 3) Re-examination of the polyol pathway and previously unrecognized rate-limiting steps; 4) The significance of disturbance to membrane metabolism; and 5) The effect of oxidation on basal HMPS activity and oxidative resistance. These studies are based on data obtained over the past two years. We have found evidence of: 1) competition for NADPH between aldose reductase and glutathione reductase and 2) prominent changes in membrane metabolites in the diabetic rats. We will employ biochemical procedures as well as biophysical methods such as nuclear magnetic resonance spectroscopy to examine the interaction of various NADPH-requiring pathways and electron paramagnetic resonance spectroscopy to probe membrane structural change. These studies are crucial to the understanding of diabetic cataractogenesis. Studies on oxidative resistance can pave the groundwork for the design of non-surgical anti-senile cataract therapy.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
5R01EY004424-06
Application #
3258824
Study Section
Visual Sciences A Study Section (VISA)
Project Start
1983-07-01
Project End
1991-06-30
Budget Start
1988-07-01
Budget End
1989-06-30
Support Year
6
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Massachusetts Eye and Ear Infirmary
Department
Type
DUNS #
073825945
City
Boston
State
MA
Country
United States
Zip Code
02114
Cheng, H M; Cheng, F Y; Xiong, H et al. (1996) The further metabolism of sorbitol-3-phosphate and fructose-3-phosphate in the mature rat lens. Ophthalmic Res 28:57-63
Cheng, H M; Xiong, J; Hirose, S et al. (1996) Nuclear magnetic resonance studies of sugar metabolism in the human infant lens. Ophthalmic Res 28 Suppl 2:5-10
Cheng, H M; Cheng, F Y; Tanaka, G H et al. (1995) Manipulating rat lens glucose metabolism with exogenous substrates. Exp Eye Res 61:479-86
Tsubota, K; Yoshida, M; Toda, T et al. (1993) Aldose reductase inhibition and the phosphorus-31 profile of the intact diabetic rat lens. Ophthalmic Res 25:393-9
Cheng, H M; Yoshida, A; Xiong, H et al. (1991) The effect of insulin and aldose reductase inhibition on the phosphate metabolism of streptozotocin-diabetic rat lens. Exp Eye Res 53:805-8
Cheng, H M; Xiong, J; Tanaka, G et al. (1991) Analysis of concurrent glucose consumption by the hexose monophosphate shunt, glycolysis, and the polyol pathway in the crystalline lens. Exp Eye Res 53:363-6
Cheng, H M; Xiong, H; Xiong, J et al. (1990) Metabolic studies of galactosemic cataract. Exp Eye Res 51:345-9
Tsubota, K; Krauss, J M; Kenyon, K R et al. (1989) Lens redox fluorometry: pyridine nucleotide fluorescence and analysis of diabetic lens. Exp Eye Res 49:321-34
Cheng, H M; Hirose, K; Xiong, H et al. (1989) Polyol pathway activity in streptozotocin-diabetic rat lens. Exp Eye Res 49:87-92
Cheng, H M; Xiong, H; Hirose, K (1989) Generation of alpha-L-glycerophosphate in the lens. Exp Eye Res 49:281-5

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