We have shown that the kidney adapts to a change in the dietary intake of sulfur amino acids. A diet low in methionine and taurine results in diminished urinary taurine excretion with greater taurine accumulation by collagenase-isolated tubules and brush border membrane vesicles (BBMV). A high-taurine diet results in hypertaurinuria and diminished tubule and BBMV uptake. Kinetic analysis indicates that the Km of uptake at the high-affinity Beta-amino acid accumulation site is unchanged, but that the Vmax rises in animals fed the low-sulfur-amino-acid diet and falls in those on the high-taurine diet. The signal for this adaptive response is uncertain. We plan to explore four possible mechanisms for taurinuria: 1) The prevailing plasma taurine concentration may govern the adaptive response. This will be tested by acutely changing plasma taurine by infusing taurine, Beta-alanine and hypotaurine and measuring changes in tissue and urine taurine and BBMV uptake in animals on all three diets. 2) Tissue taurine levels govern the adaptive response. With Beta-alanine and guan idoethane sulfonate (GES) in the drinking water, tissue taurine levels will fall. The effect of these maneuvers on excretion and BBMV uptake will be explored. 3) Changes in sulfur amino acid intake may alter sulfhydryl groups in the membrane which perturbs sodium-taurine interactions. We will determine whether glutathione content and Gamma-glutamyl transferase in BBMV are changed by diet, whether binding of 14C-N-ethylmaleimide is changed and whether ionophores mimic or perturb the altered taurine uptake by BBMV. 4) Fasting may blunt the adaptive response by altering plasma taurine levels or by interaction of taurine with ketones of fasting. The effect of ketones and PAH on BBMV uptake will be measured. Finally, studies in 14-day-old rats which fail to adapt and of other sulfur amino acid uptake will provide additional insights into the mechanisms of the adaptive response.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK037223-02
Application #
3236001
Study Section
General Medicine B Study Section (GMB)
Project Start
1985-09-01
Project End
1986-12-31
Budget Start
1986-01-01
Budget End
1986-12-31
Support Year
2
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of California Davis
Department
Type
Schools of Medicine
DUNS #
094878337
City
Davis
State
CA
Country
United States
Zip Code
95618
Chesney, R W; Helms, R A; Christensen, M et al. (1998) The role of taurine in infant nutrition. Adv Exp Med Biol 442:463-76
Chesney, R W; Helms, R A; Christensen, M et al. (1998) An updated view of the value of taurine in infant nutrition. Adv Pediatr 45:179-200
Matsell, D G; Bennett, T; Han, X et al. (1997) Regulation of the taurine transporter gene in the S3 segment of the proximal tubule. Kidney Int 52:748-54
Koo, W W; Chesney, R W; Mitchell, N (1995) Case report: effect of pregnancy on idiopathic juvenile osteoporosis. Am J Med Sci 309:223-5
Panchenko, E L; Chesney, R W; Roy 3rd, S et al. (1994) The differential diagnostic value of urinary enzyme and amino acid excretion in children with nephrotic syndrome. Pediatr Nephrol 8:142-7
Jones, D P; Jiang, B; Chesney, R W (1994) Regulation of taurine transport by external taurine concentration and medium osmolality in renal tubular cells in culture. Adv Exp Med Biol 359:131-8
Chesney, R W; Jones, D; Zelikovic, I (1993) Renal amino acid transport: cellular and molecular events from clearance studies to frog eggs. Pediatr Nephrol 7:574-84
Chesney, R W; Budreau, A M (1993) Efflux of taurine from renal brush border membrane vesicles: is it adaptively regulated? Pediatr Nephrol 7:35-40
Jones, D P; Miller, L A; Chesney, R W (1993) Polarity of taurine transport in cultured renal epithelial cell lines: LLC-PK1 and MDCK. Am J Physiol 265:F137-45
Jones, D P; Chesney, R W (1992) Development of tubular function. Clin Perinatol 19:33-57

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