Distribution of cytochrome P-450 4A and 4F isoforms along the nephron in mice.
The production of 20-hydroxyeicosatetraenoic acid (20-HETE) in the kidney is thought to be involved in the control of renal vascular tone and tubular sodium and chloride reabsorption. 20-HETE production in the kidney has been extensively studied in rats and humans and occurs primarily via the actions of P-450 enzymes of the CYP4A and -4F families. Recent advancements in molecular genetics of the mouse have made it possible to disrupt genes in a cell-type-specific fashion. These advances could help in the creation of models that could distinguish between the vascular and tubular actions of 20-HETE. However, isoforms of the CYP4A and -4F families that may be responsible for the production of 20-HETE in the vascular and tubular segments in the kidney of the mouse are presently unknown. The goal of this study was to identify the isoforms of the CYP4A and -4F families along the nephron by RT-PCR of RNA isolated from microdissected renal blood vessels and nephron segments from 16- to 24-wk-old male and female C57BL/6J mice. CYP4A and -4F isoforms were detected in every segment analyzed, with sex differences only observed in the proximal tubule and glomeruli. In the proximal tubular segments from male mice, the 4A10 and -12 isoforms were present, whereas the 4A10 and -14 isoforms were detected in segments from female mice. In glomeruli, sex differences in the expression pattern of CYP4F isoforms were also observed, with male mice expressing the 4F13, -14, and -15 isoforms, whereas female mice expressed the 4F13, -16, and -18 isoforms. These results demonstrate that isolated nephron and renal vessel segments express multiple isoforms of the CYP4A and -4F families; therefore, elimination of a single CYP4A or -4F isoform may not decrease 20-HETE production in all nephron segments or the renal vasculature of male and female mice. However, the importance of CYP4A vs. -4F isoforms to the production of 20-HETE in each of these renal tubular and vascular segments of the mouse remains to be determined.
Stec
David E
DE
Department of Physiology and Biophysics, Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson 39216-4505, USA. dstec@physiology.umsmed.edu
Flasch
Averia
A
Roman
Richard J
RJ
White
Jared A
JA
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D042926:Cytochrome P-450 CYP4A; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics*; D005260:Female; D015870:Gene Expression / Q000502:physiology; D007536:Isomerism; D007685:Kidney Tubules, Collecting / Q000098:blood supply / Q000502:physiology; D007687:Kidney Tubules, Proximal / Q000098:blood supply / Q000502:physiology; D008138:Loop of Henle / Q000098:blood supply / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008833:Microcirculation; D008861:Microsomes / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000235:genetics*; D009399:Nephrons / Q000098:blood supply / Q000502:physiology*; D012079:Renal Circulation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012727:Sex Characteristics
D016718:Arachidonic Acid; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D042926:Cytochrome P-450 CYP4A