Metabolism of cysteine and cysteinesulfinate in rat kidney tubules

Journal Article · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5018583

De La Rosa, J; Stipanuk, M H

In studies with rat hepatocytes, hypotaurine plus taurine production accounted for less than 5% of the total amount of cysteine (CYS) catabolized, whereas more than 90% of the metabolized cysteinesulfinate (CSA) was converted to taurine plus hypotaurine. Similar studies have been carried out with kidney tubules isolated from fed rats and incubated with 2 mM (1-/sup 14/C)CYS or 25 mM (1-/sup 14/C)CSA at 37/sup 0/C for up to 40 min. The production of /sup 14/CO/sub 2/ from CSA (3.1 +/- 1.3 nmol/sup ./ min/sup -1//sup ./ mg dry wt/sup -1/) was equivalent to the accumulation of N in NH/sub 4//sup +/ plus glutamate. Substantial oxidation of CYS was observed (16 +/- 11 nmol CO/sub 2/ x min/sup -1/ x mg dry wt/sup -1/), but only 12% of the expected amount of N was recovered as NH/sub 4//sup +/ plus glutamate. Accumulation of hypotaurine plus taurine was equivalent to 20% of the observed rate of /sup 14/CO/sub 2/ production from CSA but accounted for only 2% of the observed rate of /sup 14/CO/sub 2/ production from CYS. Addition of unlabeled CSA to incubations with varying levels of CYS had no effect on production of /sup 14/CO/sub 2/. Addition of 2 mM ..cap alpha..-ketoglutarate to the incubation mixtures resulted in an increased in /sup 14/CO/sub 2/ production from CSA to 290% of the control level but had no effect on CYS oxidation. In agreement with the authors findings for rat hepatocytes, these data suggest that most metabolism of CYS by the rat kidney tubule occurs by a CSA-independent pathway. However, in contrast to the metabolism of CSA almost entirely to taurine in the hepatocyte, kidney tubules appeared to metabolize CSA primarily by the transamination pathway.

• Research Organization: Cornell Univ., Ithaca, NY
• OSTI ID: 5018583
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CYSTEINE
METABOLISM
BIOLOGICAL PATHWAYS
CARBON 14 COMPOUNDS
CARBON DIOXIDE
LIVER CELLS
RATS
TAURINE
TRACER TECHNIQUES
TUBULES
AMINES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BODY
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
ISOTOPE APPLICATIONS
KIDNEYS
LABELLED COMPOUNDS
MAMMALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
RODENTS
SOMATIC CELLS
SULFONIC ACIDS
THIOLS
VERTEBRATES
550501* - Metabolism- Tracer Techniques