Dysfunction of myocardial taurine transport and effect of taurine supplement in rats with isoproterenol-induced myocardial injury.
OBJECTIVE
To study the alterations of myocardial taurine transport function, taurine transporter (TAUT), and cysteine sulfinate decarboxylase (CSD) mRNA as well as effect of exogenous taurine in rats with isoproterenol (ISO)-induced cardiomegaly.


METHODS
[3H]-Taurine uptake and release on myocardium were determined. Binding sites of [3H]-taurine for myocardial sarcolemma were measured. TAUT and CSD mRNA levels were assayed using competitive quantitative reverse transcriptase polymerase chain reaction (RT-PCR).


RESULTS
ISO group as compared with control group, myocardial taurine uptake markedly reduced, taurine release obviously increased; Bmax value of [3H]-taurine binding on cardiac sarcolemma reduced by 42% (P<0.05); TAUT and CSD mRNA levels decreased by 40% and 38% (P<0.05), respectively. ISO+taurine group as compared with ISO-treated group, the amounts of taurine uptake and TAUT mRNA returned to normal; taurine release reduced; Bmax increased by 92% (P<0.01), and CSD mRNA content augmented by 23% (P<0.05). There were no statistical differences of Kd values among the four groups (P>0.05).


CONCLUSIONS
The data indicate that the failure to generate sufficient TAUT on myocardial sarcolemma may be the fundamental abnormality in ISO-induced cardiac injury. The mechanism by which administration of taurine considerably improves ISO-induced cardiac damage is probably to increase the expression of TAUT gene and recover taurine transport function.
Shi
Yan-Rong
YR
Bu
Ding-Fang
DF
Qi
Yong-Fen
YF
Gao
Lin
L
Jiang
Hong-Feng
HF
Pang
Yong-Zheng
YZ
Tang
Chao-Shu
CS
Du
Jun-Bao
JB
D000818:Animals; D001693:Biological Transport, Active; D002262:Carboxy-Lyases / Q000378:metabolism; D006332:Cardiomegaly / Q000139:chemically induced / Q000378:metabolism*; D007545:Isoproterenol; D008297:Male; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013654:Taurine / Q000493:pharmacokinetics*
D013654:Taurine; D002262:Carboxy-Lyases; C019972:sulfoalanine decarboxylase; D007545:Isoproterenol