Increased excretion of taurine, hypotaurine and sulfate after hypotaurine loading and capacity of hypotaurine metabolism in rats.
Hypotaurine was intraperitoneally injected into rats and urinary taurine, hypotaurine and sulfate were determined. Taurine excretion increased dose-dependently when 1 to 7 mmol of hypotaurine per kg of body weight was administered. The total excretion and the increased excretion (difference of those before and after the loading) were 2328 +/- 219 and 1948 +/- 153 mumol per kg of body weight per day, respectively, at 7 mmol of hypotaurine loading. Hypotaurine excretion was negligible in the normal rat urine. However, it increased when hypotaurine was loaded. Hypotaurine excretion at 7 mmol of hypotaurine loading was 2282 +/- 258 mumol per kg per day. These results indicate that the capacity of hypotaurine oxidation to taurine in rats is more than 2 mmol per kg per day under the present experimental conditions. Sulfate excretion increased significantly when more than 3 mmol of hypotaurine per kg of body weight was injected. When 5 and 7 mmol of hypotaurine was loaded, the increased excretion of sulfate was 619 +/- 205 and 632 +/- 118 mumol per kg per day, respectively. It was confirmed that in vitro incubation of hypotaurine and 2-oxoglutarate with rat liver homogenate results in the formation of L-glutamate and sulfate. Present findings indicate that hypotaurine in vivo was mainly oxidized to taurine and that it was partly metabolized to sulfate via transamination reaction.
Fujiwara
M
M
Department of Biochemistry, Okayama University Medical School, Japan.
Ubuka
T
T
Abe
T
T
Yukihiro
K
K
Tomozawa
M
M
D000818:Animals; D007700:Kinetics; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013431:Sulfates / Q000652:urine*; D013654:Taurine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000493:pharmacokinetics / Q000652:urine*; D013997:Time Factors
D013431:Sulfates; D013654:Taurine; C003949:hypotaurine