TY - JOUR
T1 - Arginine vasotocin promotes urea permeability through urea transporter expressed in the toad urinary bladder cells
AU - Konno, Norifumi
AU - Hyodo, Susumu
AU - Matsuda, Kouhei
AU - Uchiyama, Minoru
N1 - Funding Information:
The authors thank Dr. H. Kato of Systematic Botany Laboratory, Department of Biological Science, Faculty of Urban Liberal Arts, Tokyo Metropolitan University for his kind help and suggestion regarding animal collection. We also thank Dr. T. Wakasugi, Department of Biology, Faculty of Science and Engineering, University of Toyama, for his valuable advice in the molecular biology aspects of the study. This work was supported by a Research Fellowship from the Japan Society for the Promotion of Science for Young Scientists provided to N.K.
PY - 2007
Y1 - 2007
N2 - We previously isolated a cDNA of a urea transporter (Bufo UT) from the kidney of the marine toad, Bufo marinus, and demonstrated that the Bufo UT was specifically localized on the epithelial membrane of the early distal tubules in the kidney and urinary bladder. In the present study, the function of Bufo UT was investigated using a Xenopus oocytes expression system. Further, we examined the effects of arginine vasotocin (AVT) on urea transport in isolated cells from the toad urinary bladder. When expressed in Xenopus oocytes Bufo UT induced more than a 10-fold increase in [14C]urea uptake compared with water-injected control oocytes. Phloretin, a urea transport inhibitor, fully blocked the increase of urea uptake. In epithelial cells isolated from the toad urinary bladder, addition of AVT to the medium increased the urea uptake in a concentration-dependent manner (10-12-10-8 M). To examine the relationship between the Bufo UT protein expression and an increase of urea transportability, we analyzed the time course of the Bufo UT expression levels and urea uptake in the cells treated with 10-8 M AVT. Treatment of 10-8 M AVT increased the urea uptake in the cells after 24 and 48 h incubation, but not after 12 h. According to the immunoblot analysis, UT protein expression was coincident with the results of urea uptake in the AVT-treated cells. These results suggest that Bufo UT isolated from the kidney, functions as an AVT-mediated urea transporter in the urinary bladder of the toad.
AB - We previously isolated a cDNA of a urea transporter (Bufo UT) from the kidney of the marine toad, Bufo marinus, and demonstrated that the Bufo UT was specifically localized on the epithelial membrane of the early distal tubules in the kidney and urinary bladder. In the present study, the function of Bufo UT was investigated using a Xenopus oocytes expression system. Further, we examined the effects of arginine vasotocin (AVT) on urea transport in isolated cells from the toad urinary bladder. When expressed in Xenopus oocytes Bufo UT induced more than a 10-fold increase in [14C]urea uptake compared with water-injected control oocytes. Phloretin, a urea transport inhibitor, fully blocked the increase of urea uptake. In epithelial cells isolated from the toad urinary bladder, addition of AVT to the medium increased the urea uptake in a concentration-dependent manner (10-12-10-8 M). To examine the relationship between the Bufo UT protein expression and an increase of urea transportability, we analyzed the time course of the Bufo UT expression levels and urea uptake in the cells treated with 10-8 M AVT. Treatment of 10-8 M AVT increased the urea uptake in the cells after 24 and 48 h incubation, but not after 12 h. According to the immunoblot analysis, UT protein expression was coincident with the results of urea uptake in the AVT-treated cells. These results suggest that Bufo UT isolated from the kidney, functions as an AVT-mediated urea transporter in the urinary bladder of the toad.
KW - Arginine vasotocin (AVT)
KW - Bufo marinus
KW - Urea
KW - Urea transporter (UT)
KW - Urinary bladder
UR - http://www.scopus.com/inward/record.url?scp=34250661849&partnerID=8YFLogxK
U2 - 10.1016/j.ygcen.2006.12.007
DO - 10.1016/j.ygcen.2006.12.007
M3 - 学術論文
C2 - 17270186
AN - SCOPUS:34250661849
SN - 0016-6480
VL - 152
SP - 281
EP - 285
JO - General and Comparative Endocrinology
JF - General and Comparative Endocrinology
IS - 2-3
ER -
