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Hitomi Takada - One of the best experts on this subject based on the ideXlab platform.

  • urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    Background The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels.

  • urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls (P < 0.0001). After administration of tolvaptan, urinary AQP2/creatinine ratios decreased by 45.0 % at 4 h and 77.0 % at 8 h. Similarly, urinary osmolarity decreased by 42.0 % at 4 h and 41.5 % at 8 h. Urinary AQP2 levels and urinary osmolarity significantly correlated at the baseline and at all time points after tolvaptan administration. The degree of the decrease in urinary AQP2 levels and degree of the decrease in urinary osmolarity correlated significantly at 4 h (r = 0.452, P = 0.009) and 8 h (r = 0.384, P = 0.030) after tolvaptan administration. These results indicate that the vasopressin–AQP2 system plays a major role in fluid retention in cirrhosis and that the Pharmacological Effect of tolvaptan to inhibit water reabsorption can be monitored by measurement of the dynamics of urinary AQP2 levels.

  • Urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    Background The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Methods Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. Results At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls ( P  

  • Urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of gastroenterology, 2015
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls (P 

Hiroyuki Nakanishi - One of the best experts on this subject based on the ideXlab platform.

  • urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    Background The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels.

  • urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls (P < 0.0001). After administration of tolvaptan, urinary AQP2/creatinine ratios decreased by 45.0 % at 4 h and 77.0 % at 8 h. Similarly, urinary osmolarity decreased by 42.0 % at 4 h and 41.5 % at 8 h. Urinary AQP2 levels and urinary osmolarity significantly correlated at the baseline and at all time points after tolvaptan administration. The degree of the decrease in urinary AQP2 levels and degree of the decrease in urinary osmolarity correlated significantly at 4 h (r = 0.452, P = 0.009) and 8 h (r = 0.384, P = 0.030) after tolvaptan administration. These results indicate that the vasopressin–AQP2 system plays a major role in fluid retention in cirrhosis and that the Pharmacological Effect of tolvaptan to inhibit water reabsorption can be monitored by measurement of the dynamics of urinary AQP2 levels.

  • Urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    Background The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Methods Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. Results At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls ( P  

  • Urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of gastroenterology, 2015
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls (P 

Wei-chiang Shen - One of the best experts on this subject based on the ideXlab platform.

  • Reversible lipidization prolongs the Pharmacological Effect, plasma duration, and liver retention of octreotide.
    Pharmaceutical research, 2005
    Co-Authors: Liyun Yuan, Jeffrey Wang, Wei-chiang Shen
    Abstract:

    Purpose. Octreotide (OCT) was reversibly lipidized to improve the Pharmacological Effect and to increase the plasma half-life and the liver retention of OCT for greater therapeutic potential in the treatment of liver cancers such as hepatocellular carcinoma.

  • Reversible Lipidization Prolongs the Pharmacological Effect, Plasma Duration, and Liver Retention of Octreotide
    Pharmaceutical Research, 2005
    Co-Authors: Liyun Yuan, Jeff Wang, Wei-chiang Shen
    Abstract:

    Purpose. Octreotide (OCT) was reversibly lipidized to improve the Pharmacological Effect and to increase the plasma half-life and the liver retention of OCT for greater therapeutic potential in the treatment of liver cancers such as hepatocellular carcinoma. Methods. OCT was chemically modified using reversible aqueous lipidization (REAL) technology. REAL-modified OCT (REAL-OCT) was characterized with high performance liquid chromatography (HPLC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. A single dose of OCT or REAL-OCT or vehicle only was subcutaneously administered to male Sprague-Dawley rats, and the plasma growth hormone (GH) levels were measured after an intravenous injection of 2.5 μg/kg of growth hormone releasing factor (GRF) to assess the ability of REAL-OCT on GH inhibition. Radio-iodinated Tyr^3-OCT (TOC) and REAL-TOC were used for pharmacokinetic studies. Results. At 0.1 mg/kg, REAL-OCT inhibited the GRF-induced GH surge in rats for a greater than 24-h period in comparison to the 6-h period for OCT. The distribution and elimination half-life for ^125I-REAL-TOC were 1.4 h and 6.6 h, respectively, which were significantly longer than those of ^125I-TOC. Sustained high blood concentrations and reduced in vivo degradation were observed for ^125I-REAL-TOC. In addition, ^125I-REAL-TOC appeared to be targeted to the liver with persistent high liver retention. Conclusions. REAL-OCT has a significantly enhanced Pharmacological Effect, and this is most likely due to the favorable changes in the pharmacokinetic parameters upon lipidization. The observed liver targeting Effect of REAL-TOC suggests that REAL-OCT might be advantageous over OCT in treating liver cancers.

Shoko Suzuki - One of the best experts on this subject based on the ideXlab platform.

  • urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    Background The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels.

  • urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls (P < 0.0001). After administration of tolvaptan, urinary AQP2/creatinine ratios decreased by 45.0 % at 4 h and 77.0 % at 8 h. Similarly, urinary osmolarity decreased by 42.0 % at 4 h and 41.5 % at 8 h. Urinary AQP2 levels and urinary osmolarity significantly correlated at the baseline and at all time points after tolvaptan administration. The degree of the decrease in urinary AQP2 levels and degree of the decrease in urinary osmolarity correlated significantly at 4 h (r = 0.452, P = 0.009) and 8 h (r = 0.384, P = 0.030) after tolvaptan administration. These results indicate that the vasopressin–AQP2 system plays a major role in fluid retention in cirrhosis and that the Pharmacological Effect of tolvaptan to inhibit water reabsorption can be monitored by measurement of the dynamics of urinary AQP2 levels.

  • Urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    Background The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Methods Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. Results At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls ( P  

  • Urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of gastroenterology, 2015
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls (P 

Natsuko Nakakuki - One of the best experts on this subject based on the ideXlab platform.

  • urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    Background The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels.

  • urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls (P < 0.0001). After administration of tolvaptan, urinary AQP2/creatinine ratios decreased by 45.0 % at 4 h and 77.0 % at 8 h. Similarly, urinary osmolarity decreased by 42.0 % at 4 h and 41.5 % at 8 h. Urinary AQP2 levels and urinary osmolarity significantly correlated at the baseline and at all time points after tolvaptan administration. The degree of the decrease in urinary AQP2 levels and degree of the decrease in urinary osmolarity correlated significantly at 4 h (r = 0.452, P = 0.009) and 8 h (r = 0.384, P = 0.030) after tolvaptan administration. These results indicate that the vasopressin–AQP2 system plays a major role in fluid retention in cirrhosis and that the Pharmacological Effect of tolvaptan to inhibit water reabsorption can be monitored by measurement of the dynamics of urinary AQP2 levels.

  • Urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of Gastroenterology, 2016
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    Background The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Methods Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. Results At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls ( P  

  • Urinary excretion of the water channel aquaporin 2 correlated with the Pharmacological Effect of tolvaptan in cirrhotic patients with ascites
    Journal of gastroenterology, 2015
    Co-Authors: Hiroyuki Nakanishi, Masayuki Kurosaki, Takanori Hosokawa, Yuka Takahashi, Jun Itakura, Shoko Suzuki, Yutaka Yasui, Nobuharu Tamaki, Natsuko Nakakuki, Hitomi Takada
    Abstract:

    The water channel aquaporin 2 (AQP2) at the apical membrane of renal collecting duct cells mediates water reabsorption. The expression of AQP2 at the apical membrane is tightly regulated by vasopressin and was quantitated by measurement of the urinary form by a recently developed ELISA. Tolvaptan, an antagonist of vasopressin type 2 receptor, inhibits water reabsorption in cirrhosis. The aim of this study was to determine the correlation between the Pharmacological Effect of tolvaptan and the dynamics of urinary AQP2 levels. Tolvaptan was administered to 41 cirrhotic patients with ascites unresponsive to standard diuretic therapy. Urinary excretion of AQP2 and urinary osmolarity were measured at the baseline and at 4, 8, and 24 h after administration of tolvaptan. At the baseline, urinary AQP2/creatinine ratios were significantly higher in cirrhotic patients with ascites than in healthy controls (P