Regulation of cytochrome P-450 4A activity by peroxisome proliferator-activated receptors in the rat kidney.
The localization of cytochrome P-450 4A, peroxisome proliferator-activated receptor (PPAR) alpha, and PPARgamma proteins, and the inducibility of P-450 4A expression and activity by PPAR agonists were determined in the rat kidney. The expressions of these proteins in isolated nephron segments were evaluated by immunoblot analysis, and the production of 20-hydroxyeicosatetraenoic acid (20-HETE) was measured as P-450 4A activity. P-450 4A proteins were expressed predominantly in the proximal tubule (PT), with lower expression in the preglomerular arteriole (Art), glomerulus (Glm), and medullary thick ascending limb (mTAL), but their expression was not detected in the inner medullary collecting duct (IMCD). PPARalpha protein was expressed in the PT and mTAL, and PPARgamma protein was expressed in the IMCD and mTAL. Treatment with clofibrate, the PPARalpha agonist, increased P-450 4A protein levels and the production of 20-HETE in microsomes prepared from the renal cortex, whereas treatment with pioglitazone, the PPARgamma agonist, affected neither of them. These results indicate that PPARalpha and PPARgamma proteins are localized in different nephron segments and the inducibility of P-450 4A expression and activity by the PPAR agonists correlates with the nephron-specific localization of the respective PPAR isoforms.
Ishizuka
Tsuneo
T
Department of Nephrology, Endocrinology, and Hypertension, Tohoku University Graduate School of Medicine, Sendai, Japan.
Ito
Osamu
O
Tan
Liping
L
Ogawa
Susumu
S
Kohzuki
Masahiro
M
Omata
Ken
K
Takeuchi
Kazuhisa
K
Ito
Sadayoshi
S
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D042926:Cytochrome P-450 CYP4A / Q000096:biosynthesis / Q000378:metabolism*; D006893:Hydroxyeicosatetraenoic Acids / Q000378:metabolism; D066298:In Vitro Techniques; D007668:Kidney / Q000201:enzymology*; D007679:Kidney Medulla / Q000201:enzymology; D007685:Kidney Tubules, Collecting / Q000201:enzymology; D007687:Kidney Tubules, Proximal / Q000201:enzymology; D008297:Male; D008861:Microsomes / Q000201:enzymology; D008862:Microsomes, Liver / Q000201:enzymology; D009399:Nephrons / Q000201:enzymology; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000819:agonists / Q000502:physiology*; D014157:Transcription Factors / Q000819:agonists / Q000502:physiology*
D000959:Antihypertensive Agents; D006893:Hydroxyeicosatetraenoic Acids; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; D042926:Cytochrome P-450 CYP4A