Downregulation of AQP2 expression in the kidney of polydipsic STR/N mice.
Aquaporin-2 (AQP2) is responsible for the concentration of urine in the kidney collecting tubule under the regulation of vasopressin. The mRNA level of this water channel in polydipsic STR/N mice was extremely reduced compared with that in normal ICR mice. In male mice, reduction of the AQP2 mRNA level was not evident at 3 wk of age, at which time water intake was not increased. At 10 wk of age, however, the AQP2 mRNA level was reduced to 10% of that in control mice, whereas water intake was increased by 36%. At 44 wk, the water intake became five times that of the control ICR mice, and the AQP2 mRNA level in these polydipsic mice was only approximately 5% of control. Similar changes were observed in the AQP2 protein level, suggesting that the mRNA level of AQP2 reflects the protein level of AQP2. These inverse changes in the AQP2 mRNA level and water intake were also evident in female mice. The data imply that polydipsia in STR/N mice may have affected AQP2 mRNA transcription in the kidney, resulting in reduced AQP2 expression, which would contribute to a reduction in overretention of water.
Tsumura
Keiko
K
Department of Molecular Oral Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima-shi, Tokushima 770-8504, Japan.
Li
Xuefei
X
Murdiastuti
Kwartarini
K
Parvin
Most Nahid
MN
Akamatsu
Tetsuya
T
Yao
Chenjuan
C
Kanamori
Norio
N
Inenaga
Kiyotoshi
K
Yamashita
Hiroshi
H
Hosoi
Kazuo
K
D000367:Age Factors; D000818:Animals; D051399:Aquaporin 2 / Q000378:metabolism*; D020346:Aquaporins / Q000378:metabolism*; D001835:Body Weight; D004231:Diuresis / Q000187:drug effects*; D015536:Down-Regulation; D004327:Drinking Behavior; D005260:Female; D007668:Kidney / Q000378:metabolism*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008815:Mice, Inbred Strains; D009994:Osmolar Concentration; D011141:Polyuria / Q000209:etiology / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013894:Thirst
C496024:Aqp2 protein, mouse; D051399:Aquaporin 2; D020346:Aquaporins; D012333:RNA, Messenger