title: [Expressions of S1P1-3 in the corpus cavernosum of castrated male rats].
abstract: OBJECTIVE
  To investigate the expressions of sphingosine-1-phosphate receptors 1-3 (S1P1- 3) in the corpus cavernosum of castrated male rats and its relationship with the NOS/NO/cGMP and RhoA/Rho kinase signaling pathways.
  
  
  METHODS
  We equally randomized 18 eight-week-old healthy male SD rats into a sham-operation control, a castration, and a testosterone replacement (TR) group and harvested the bilateral testes and epididymides from the rats in the latter two groups, followed by 4 weeks of subcutaneous injection of testosterone propionate at 3 mg per kilogram of the body weight per day for those in the TR group and that of plant oil for those in the control and castration groups. At the age of 12 weeks, we measured the serum testosterone (T) level and maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP) of the animals and determined the expressions of SlP1-3, eNOS, P-eNOS, ROCK1, and ROCK2 in the corpus cavernosum by Western blot and immunohistochemistry.
  
  
  RESULTS
  The serum T level was significantly decreased in the rats of the castration group as compared with those of the control and TR groups ([0.41 ± 0.04] vs [16.01 ± 1.02] and [15.84 ± 1.32] nmol/L, P < 0.01), with no statistically significant difference between the latter two groups. The ICPmax/MAP at 0 V, 3 V, and 5 V electric stimulation was remarkably lower in the rats of the castration group (0.088 ± 0.014, 0.323 ± 0.014, and 0.432 ± 0.012) than in those of the control group (0.155 ± 0.011, 0.711 ± 0. 010, and 0.819 ± 0.024) and TR group (0.153 ± 0.012, 0.696 ± 0.017, and 0.763 ± 0.027) (P < 0.01), with no significant difference between the latter two groups. With GAPDH as internal control, the animals of the castration group showed markedly reduced expressions of S1P1 ([49.99 ± 3.39]%), eNOS ([46.82 ± 3.81]%) , and P-eNOS ([45.42 ± 4.35]%) in comparison with those in the control group ([72.57 ± 3.06], [89.76 ± 3.98], and [82.53 ± 8.92] and TR group ([71.77 ± 4.43], [87.19 ± 4.23], and [79.82 ± 7.38]%) (P < 0.01) , while the expressions of S1P2, S1P3, ROCK1, and ROCK2 were significantly upregulated in the castration group ([82.35 ± 4.13], [61.03 ± 5.14], [74.50 ± 4.02], and [69.83 ± 5.75]%) as compared with those in the control group ([41.67 ± 1.68], [31.66 ± 2.67], [35.69 ± 5.56], and [39.85 ± 7.17]%) and TR group ([42.80 ± 3.87], [32.25 ± 4.22], 38.06 ± 5.21], and [42.36 ± 4.44]%) (P < 0.01).
  
  
  CONCLUSIONS
  Androgen deficiency induces significant reduction of ICPmax/ MAP in male rats, which is possibly associated with the decline of S1P1 in the corpus cavernosum, inhibition of the eNOS/NO/cGMP signaling pathway, increased expressions of S1P2 and S1P3, and activation of the RhoA/Rho kinase signaling pathway.
authors.forename: Xue-qin
authors.initials: XQ
authors.lastname: Chen
authors.forename: Ji-yi
authors.initials: JY
authors.lastname: Xia
authors.forename: Bo
authors.initials: B
authors.lastname: Cheng
authors.forename: Rui
authors.initials: R
authors.lastname: Jiang
mesh_terms: D000818:Animals; D008297:Male; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D009919:Orchiectomy; D010413:Penis / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D049349:Receptors, Lysosphingolipid / Q000378:metabolism*; D013739:Testosterone / Q000097:blood / Q000494:pharmacology*; D054460:rho-Associated Kinases / Q000378:metabolism
chemical_list: D049349:Receptors, Lysosphingolipid; D013739:Testosterone; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; C578418:ROCK1 protein, rat; C580818:ROCK2 protein, rat; D054460:rho-Associated Kinases