Differential regulation of ROMK expression in kidney cortex and medulla by aldosterone and potassium.
This study explores the role of K+ and aldosterone in the regulation of mRNA of the ATP-sensitive, inwardly rectifying K+ channel, ROMK, in the rat kidney. K+ deficiency downregulated ROMK mRNA in cortex to 47.1 +/- 5.1% of control (P < 0.001) and in medulla to 56.1 +/- 3. 4% (P < 0.001). High-K+ diet slightly increased ROMK mRNA in medulla to 122 +/- 9% (P < 0.05 vs. control). Adrenalectomy (Adx) downregulated cortical ROMK mRNA to 30.7 +/- 6.8% (P < 0.001 vs. control), and increased it in medulla to 138 +/- 12.9% (P < 0.02 vs. control). In Adx rats, K+ deficiency decreased ROMK mRNA in cortex and medulla similar to intact rats. The alpha1- and beta1-Na-K-ATPase subunits were regulated in parallel to that of ROMK. In medulla, ROMK mRNA correlated with serum K+ concentration at R = 0.9406 (n = 6, P < 0.001) and alpha1-Na-K-ATPase mRNA at R = 0.9756 (n = 6, P < 0.001). ROMK2 also correlated with serum K+ concentration (R = 0.895; n = 6, P < 0.01). These results show that cortical ROMK expression is regulated by aldosterone and K+, whereas the medullary ROMK mRNA is regulated by serum K+.
Wald
H
H
Nephrology and Hypertension Services, Hadassah University Hospital, Jerusalem 91120, Israel.
Garty
H
H
Palmer
L G
LG
Popovtzer
M M
MM
D000315:Adrenalectomy; D000450:Aldosterone / Q000097:blood / Q000502:physiology*; D000818:Animals; D015536:Down-Regulation; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D007672:Kidney Cortex / Q000187:drug effects / Q000378:metabolism*; D007679:Kidney Medulla / Q000187:drug effects / Q000378:metabolism*; D046911:Macromolecular Substances; D008297:Male; D011188:Potassium / Q000097:blood / Q000494:pharmacology*; D015221:Potassium Channels / Q000096:biosynthesis / Q000235:genetics*; D024661:Potassium Channels, Inwardly Rectifying; D011191:Potassium Deficiency / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D012044:Regression Analysis; D012964:Sodium / Q000097:blood; D000254:Sodium-Potassium-Exchanging ATPase / Q000096:biosynthesis / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects
C510692:Kcnj1 protein, rat; D046911:Macromolecular Substances; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger; D000450:Aldosterone; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium