Submitted on January 7, 2004
Accepted on July 18, 2004
Taurine increases glucose sensitivity of UCP2-overexpressing 
-cells by ameliorating mitochondrial metabolism
Jin Han1, Jae Hoon Bae2, So-Yeon Kim2, Hyun-Young Lee2, Byeong-Churl Jang3, In-Kyu Lee3, Chi-Heum Cho3, Jeong-Geun Lim3, Seong-Il Suh3, Taeg-Kyu Kwon3, Jong-Wook Park3, Shin Young Ryu4, Won-Kyung Ho4, Yung-E Earm4, and Dae-Kyu Song5*
1 Department of Physiology & Biophysics, College of Medicine, Inje University, Busan, Korea, Republic of
2 Department of Physiology, Keimyung University School of Medicine, Daegu, Korea, Republic of
3 Chronic Disease Research Center, Keimyung University School of Medicine, Daegu, Korea, Republic of
4 Department of Physiology, College of Medicine, Seoul National University, Seoul, Korea, Republic of
5 Department of Physiology, Keimyung University School of Medicine, Daegu, Korea, Republic of; Chronic Disease Research Center, Keimyung University School of Medicine, Daegu, Korea, Republic of
* To whom correspondence should be addressed. E-mail: dksong{at}kmu.ac.kr.
A low taurine diet during fetal or early postnatal life causes abnormal pancreatic 
-cell
development. Tissue and plasma taurine concentrations can also be low in diabetic
patients. We examined the effect of taurine on impaired glucose responses in diabetic rat
-cells adenovirally-overexpressing uncoupling protein (UCP2), which is up-regulated
in obesity-related type-2 diabetes. We found that taurine pretreatment restored the
ATP/ADP ratio and glucose-stimulated insulin secretion (GSIS) in UCP2-infected islets.
KATP channel sensitivity to dihydroxyacetone, another insulin secretagogue, was similar
in both UCP2-infected and control -cells. In freshly isolated mitochondria from UCP2-
overexpressing INS-1 -cells, methyl pyruvate-mediated mitochondrial Ca2+ increase
was significantly ameliorated by taurine. A mitochondrial Ca2+ uniporter blocker,
ruthenium red, inhibited the action of taurine. This study suggests that taurine enhances
the glucose sensitivity of UCP2-overexpressing -cells, probably by increasing
mitochondrial Ca2+ influx through the Ca2+ uniporter, thereby enhancing mitochondrial
metabolic function and increasing the ATP/ADP ratio.
