Effect of salt and water intake on epithelial sodium channel mRNA abundance in the kidney of salt-sensitive Sabra rats.
1. The level of mRNA expression of epithelial sodium channel (ENaC) subunits was studied in a salt-dependent hypertensive rat strain (Sabra). These rats exhibit high vasopressin levels compared with their normotensive counterparts. We also investigated whether this expression is influenced by changes in the sodium intake/aldosterone axis or in the fluid intake/vasopressin axis. 2. A higher expression of beta- and gamma-subunit mRNA was found in salt-sensitive compared with salt-resistant rats on a normal salt diet. A high-sodium diet did not alter mRNA abundance in either substrain. In contrast, water supplementation in salt-sensitive rats fed the high-sodium diet induced a marked reduction in mRNA abundance of beta- and gamma-subunits. 3. The present study provides evidence that beta- and gamma-subunits of ENaC are differently expressed in the kidney of salt-sensitive and salt-resistant Sabra rats and that their abundance is regulated by vasopressin, not by sodium intake. These results are consistent with the hypothesis that increased vasopressin-dependent ENaC expression and activity may contribute to the pathogenesis of hypertension in salt-sensitive Sabra rats.
Nicco
Carole
C
INSERM Unité 367, Paris, France.
Bankir
Lise
L
Bouby
Nadine
N
D000450:Aldosterone / Q000097:blood / Q000378:metabolism; D000818:Animals; D004195:Disease Models, Animal; D004326:Drinking / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006973:Hypertension / Q000235:genetics; D007672:Kidney Cortex / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D021122:Protein Subunits / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D015222:Sodium Channels / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D017673:Sodium Chloride, Dietary / Q000378:metabolism / Q000494:pharmacology*; D013997:Time Factors; D015854:Up-Regulation; D014667:Vasopressins / Q000097:blood / Q000378:metabolism
D021122:Protein Subunits; D012333:RNA, Messenger; D015222:Sodium Channels; D017673:Sodium Chloride, Dietary; D014667:Vasopressins; D000450:Aldosterone