Increased expression of aquaporin water channels in hypothyroid rat kidney.
The present study was aimed to determine the molecular mechanisms underlying the water retention associated with hypothyroidism. Male Sprague-Dawley rats (200-220g) were experimentally induced of hypothyroidism by treatment with methimazole in drinking water (0.04%) for 8 weeks. In the experimental group, serum concentrations of thyroxine and triiodothyronine were significantly decreased. The expression of aquaporin 2 (AQP2) was significantly increased in the cortex, outer medulla, and inner medulla of the kidney. The expression of AQP1 as well as that of AQP3 was significantly increased in the cortex, though not in the medulla. The adenylyl cyclase activity provoked by arginine vasopressin (AVP), sodium fluoride, or forskolin was blunted in the hypothyroid kidney, while plasma levels of AVP were not significantly changed. The increased expression of AQP1-3 channels may in part account for the water retention in hypothyroidism.
Department of Internal Medicine, Cheju National University Medical School, Jeju 690-716, South Korea.
Chung Ho
CH
Yeum
Soo Wan
SW
Kim
Nam Ho
NH
Kim
Ki Chul
KC
Choi
Jongun
J
Lee
D000818:Animals; D051398:Aquaporin 1; D051399:Aquaporin 2; D051400:Aquaporin 3; D051403:Aquaporin 6; D020346:Aquaporins / Q000096:biosynthesis*; D000242:Cyclic AMP / Q000378:metabolism; D007037:Hypothyroidism / Q000097:blood / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
C496022:Aqp1 protein, rat; C496025:Aqp2 protein, rat; C496029:Aqp3 protein, rat; D051399:Aquaporin 2; D051403:Aquaporin 6; D020346:Aquaporins; D051398:Aquaporin 1; D051400:Aquaporin 3; D000242:Cyclic AMP