title: Metformin restores the penile expression of nitric oxide synthase in high-fat-fed obese rats.
abstract: Obesity is a well-known risk factor for erectile dysfunction, which is associated with reduced penile nitric oxide synthase (NOS) expression. Recently it was reported that metformin activates AMP-activated protein kinase (AMPK), which increases the expression of neuronal (n) NOS and endothelial (e) NOS. Thus, to evaluate whether metformin restores NOS expression in penile tissue, we measured penile expression of nNOS and eNOS after 4 weeks of metformin treatment (300 mg/kg/d) in 5-month-old high-fat-fed obese (HFO) rats. HFO rats have increased fat accumulation in visceral areas and marked suppression of nNOS and eNOS expression in penile tissue. However, metformin treatment decreased visceral fat deposition and restored nNOS and eNOS expression in penile tissue. The levels of AMPK and phosphorylated AMPK were also decreased in HFO rats but were subsequently elevated by metformin treatment. These results suggest that expression of NOS was suppressed by the high-fat diet but restored by metformin treatment. The effect of metformin on the expression of NOS may be associated with its activation of AMPK.
authors.affiliation: Department of Urology, College of Medicine, Yeungnam University, 317-1 Daemyung-Dong, Nam-Gu, Daegu 705-035, Republic of Korea.
authors.forename: Yong-Woon
authors.initials: YW
authors.lastname: Kim
authors.forename: So-Young
authors.initials: SY
authors.lastname: Park
authors.forename: Jong-Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Jung-Yoon
authors.initials: JY
authors.lastname: Huh
authors.forename: Woo-Sung
authors.initials: WS
authors.lastname: Jeon
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Yoon
authors.forename: Sung-Su
authors.initials: SS
authors.lastname: Yun
authors.forename: Ki-Hak
authors.initials: KH
authors.lastname: Moon
mesh_terms: D000263:Adenylate Kinase / Q000097:blood; D000273:Adipose Tissue / Q000033:anatomy & histology; D000818:Animals; D001835:Body Weight; D004041:Dietary Fats; D008297:Male; D008687:Metformin / Q000627:therapeutic use*; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052250:Nitric Oxide Synthase Type III / Q000235:genetics; D009765:Obesity / Q000201:enzymology* / Q000209:etiology; D009929:Organ Size; D010413:Penis / Q000201:enzymology*; D051381:Rats; D011922:Rats, Mutant Strains; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D004041:Dietary Fats; D008687:Metformin; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D000263:Adenylate Kinase