[Effects of leptin on RAAS and nitric oxide production in isolated rat glomeruli].
OBJECTIVE
To investigate the changes in angiotensinogen (AGT), angiotensin II type 1 receptor (AT(1)R), endothelial nitric oxide synthase (eNOS) mRNA and protein expressions and nitric oxide (NO) content in the rat glomeruli in response to leptin stimulation.


METHODS
The glomeruli isolated from male SD rats were stimulated with 3 nmol/L leptin for 2 h. Real-time PCR and Western blotting were performed to analyze the mRNA and protein expressions of AGT, AT(1)R and eNOS in the glomeruli, and nitrite concentration in the glomeruli was measured by nitrate reductase assay.


RESULTS
In comparison with the control group, exposure to leptin increased the mRNA levels of AGT, ATR(1) and eNOS in the isolated glomeruli by 2.69-/+0.17, 3.77-/+0.16 and 2.56-/+0.29 folds (P=0.024, 0.018 and 0.044), and their protein levels by 2.06-/+0.10, 2.67-/+0.08 and 1.61-/+0.13 folds (P=0.021, 0.015 and 0.032), respectively. The NO production in the glomeruli was also increased by 2.77-/+0.14 folds (P=0.000) following leptin exposure.


CONCLUSIONS
Leptin exposure of isolated rat glomeruli directly causes activation of the internal renal renin-angiotensin system and enhanced NO production, suggesting that leptin plays a role in the pathogenesis of maladaptation in renal hemodynamics in obesity.
Fu
Jing-yi
JY
Department of Endocrinology, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, China.
Zhang
Yi-min
YM
Zeng
Long-yi
LY
Zhang
Guo-chao
GC
Weng
Jian-ping
JP
D000818:Animals; D005786:Gene Expression Regulation / Q000187:drug effects; D007678:Kidney Glomerulus / Q000187:drug effects* / Q000378:metabolism*; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000187:drug effects*
D020738:Leptin; D012333:RNA, Messenger; D044140:Receptor, Angiotensin, Type 1; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III