Sulfate and taurine excretion in rats after L-cysteine administration.
Excretion of sulfate and taurine, two major metabolites of sulfur, was examined in rats to study the nutritional status of sulfur metabolism in the mammals. Rats maintained on a conventional laboratory diet excreted 1.83 +/- 0.14 mmol of free sulfate and 229.0 +/- 75.3 mumol of taurine/kg of body weight per day. When the diet was changed to a synthetic 25% casein diet, the taurine excretion decreased to 15% of the previous daily excretion, but sulfate excretion decreased only slightly. These decreased levels returned to the original levels when 5 mmol of L-cysteine/kg of body weight was administered into the stomach through a catheter. One week after the first L-cysteine administration, when sulfate and taurine excretion had returned to the original levels, 5 mmol of L-cysteine/kg of body weight was administered likewise. The rats excreted sulfur corresponding to about 95% of L-cysteine administered in the form of free sulfate and taurine within a few days following L-cysteine administration, and sulfate excretion was 3.5 times more than taurine excretion. These results seem to suggest that, in rats, sulfur metabolism is in a state of equilibrium and that sulfate is formed preferentially to taurine.
Yoshida
S
S
Department of Biochemistry, Okayama University Medical School, Japan.
Akagi
R
R
Ubuka
T
T
D000818:Animals; D001835:Body Weight; D003545:Cysteine / Q000008:administration & dosage / Q000378:metabolism*; D004032:Diet; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013431:Sulfates / Q000652:urine*; D013455:Sulfur / Q000378:metabolism*; D013654:Taurine / Q000652:urine*
D013431:Sulfates; D013654:Taurine; D013455:Sulfur; D003545:Cysteine