MRNA Expression of Enzymes Involved in Taurine Biosynthesis in Rat Adipose Tissues

mRNA levels of the enzymes involved in taurine synthesis were compared among 12 rat tissues. Using a quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Northern-blotting, high levels of mRNA for cysteine dioxygenase were confirmed in the liver and kidney. Unexpectedly, the mRNA levels in epididymal and perirenal white adipose tissues and interscapular brown adipose tissue were remarkably high, at least compared with those observed in the liver and kidney. Cysteine dioxygenase mRNA levels in other tissues were very low. Using Northern blotting, significant amounts of cysteine sulfinic acid decarboxylase mRNA were detected in the liver, kidney, epididymal and perirenal white adipose tissues, and brown adipose tissue, but not in other tissues. Again, the mRNA levels of cysteine sulfinic acid decarboxylase in adipose tissues were comparable to or even higher than those in the liver and kidney. The activity of cysteine sulfinic acid decarboxylase in white and brown adipose tissues was 50% to 80% of that in the liver and much higher than the values observed in kidney, lung, and brain. However, the occurrence of cysteine dioxygenase activity in adipose tissues was not confirmed.