title: Oral L-citrulline supplementation improves erectile function and penile structure in castrated rats.
abstract: OBJECTIVE
  To investigate the efficacy of oral L-citrulline for erectile dysfunction and penile structure disruption in a rat model.
  
  
  METHODS
  Male Wistar-ST rats aged 15 weeks were randomly divided into three groups as follows: sham-operated rats (control group), surgically castrated rats (castrated group) and surgically castrated rats subsequently treated with 2% L-citrulline water (castrated + L-citrulline). At 4 weeks postoperative, erectile function was assessed based on intracavernous pressure changes, followed by electrostimulation of cavernous nerves and calculation of maximum intracavernous pressure/mean arterial pressure. Penile structure was evaluated by Masson's trichrome staining and the smooth muscle-to-collagen ratio was calculated. The serum bioavailable testosterone, L-arginine, L-citrulline, N(G),N(G) -dimethylarginine and nitrogen oxide levels were evaluated.
  
  
  RESULTS
  The bioavailable testosterone concentrations were decreased in the castrated and castrated + L-citrulline groups compared with the control group at 4 weeks after surgery. The intracavernous pressure-to-mean arterial pressure and smooth muscle-to-collagen ratios were significantly decreased in the castrated group compared with the control group, but significantly increased in the castrated + L-citrulline group compared with the castrated group. The serum L-citrulline, L-arginine and N(G),N(G)-dimethylarginine levels, and the L-arginine-to-N(G),N(G)-dimethylarginine ratios were significantly increased in the castrated +L-citrulline group compared with the castrated group. The serum nitrogen oxide levels were increased in the castrated + L-citrulline group compared with the castrated group.
  
  
  CONCLUSIONS
  Oral L-citrulline can improve the erectile response to electric stimulation of cavernous nerve and penile structure in castrated rats.
authors.affiliation: Department of Hospital Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hotta
authors.forename: Arufumi
authors.initials: A
authors.lastname: Shiota
authors.forename: Tomoya
authors.initials: T
authors.lastname: Kataoka
authors.forename: Marina
authors.initials: M
authors.lastname: Motonari
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Maeda
authors.forename: Masahiko
authors.initials: M
authors.lastname: Morita
authors.forename: Kazunori
authors.initials: K
authors.lastname: Kimura
mesh_terms: D000284:Administration, Oral; D000818:Animals; D002369:Castration; D002956:Citrulline / Q000008:administration & dosage*; D004195:Disease Models, Animal; D004599:Electric Stimulation Therapy; D007172:Erectile Dysfunction / Q000188:drug therapy*; D008297:Male; D010410:Penile Erection / Q000187:drug effects*; D010413:Penis / Q000187:drug effects* / Q000294:innervation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002956:Citrulline
keywords: arginine; asymmetric dimethylarginine; castration; citrulline; erectile dysfunction