title: Activity of angiotensin peptides in clitoral cavernosum of alloxan induced diabetic rabbit.
abstract: OBJECTIVE
  To assess the role of peptides of the angiotensin (ANG) on the regulation of clitoral cavernosum tone and changes in ANG binding affinity in the rabbit with diabetes mellitus.
  
  
  METHODS
  The isometric tension measurement and in vitro autoradiography were used in sham and diabetic clitoral cavernosum.
  
  
  RESULTS
  In tension study, contractility in response to ANG I, ANG II, ANG III and ANG IV was enhanced in diabetic clitoral cavernosum strips (EC50 was 67.6 +/- 27.2, 4.3 +/- 0.4, 189.3 +/- 37.3, 443.2 +/- 0.4 nM for diabetic versus 155.2 +/- 76.1, 38.3 +/- 0.1, 528.0 +/- 75.2, 616.9 +/- 69.5 nM for sham, respectively). Contractile responses to ANG II was significantly inhibited by type 1 ANG II receptor (AT1) antagonist but not by type 2 ANG II receptor (AT2) antagonist in both groups. Percentages in contractions by ANG II (1 nM) in the presence of Dup 753 decreased significantly 36.2 +/- 4.6 to 6.3 +/- 2.4% in sham and 56.1 +/- 7.7 to 6.0 +/- 4.8% in diabetic group. The binding affinities were enhanced in diabetic clitoral cavernosum for ANG II (dissociation constant, 4.9 +/- 1.0 for sham versus 0.9 +/- 0.2 nM for diabetic) and for ANG I, ANG III, and ANG IV (inhibitory constant, 28.6 +/- 1.5, 398.7 +/- 157.2, and 3966.5 +/- 1524.1 nM for sham versus 20.6 +/- 5.7, 78.5 +/- 23.7, and 1098.7 +/- 195.5 nM, for diabetic, respectively, all p < 0.05). Sensitivities of AT1 and AT2 receptors to ANG II enhanced in diabetic than sham clitoral cavernosum tissue.
  
  
  CONCLUSIONS
  This results suggest that the contractile responses to all four ANG peptides are enhanced in the diabetic clitoral cavernosum. Enhancement of contractility in diabetic clitoral cavernosum may be related to the increased affinity to ANG II receptors for ANG peptides.
authors.affiliation: Department of Urology, Chonbuk National University Medical School, Keum-Am-Dong-San, Chonju, South Korea. rain@chonbuk.ac.kr
authors.forename: Jong Kwan
authors.initials: JK
authors.lastname: Park
authors.forename: Soon Oak
authors.initials: SO
authors.lastname: Lee
authors.forename: Wan Shou
authors.initials: WS
authors.lastname: Cui
authors.forename: Sung Zoo
authors.initials: SZ
authors.lastname: Kim
authors.forename: Gou Young
authors.initials: GY
authors.lastname: Koh
authors.forename: Kyung Woo
authors.initials: KW
authors.lastname: Cho
mesh_terms: D000496:Alloxan; D000809:Angiotensins / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D002987:Clitoris / Q000187:drug effects* / Q000502:physiology; D003921:Diabetes Mellitus, Experimental; D004195:Disease Models, Animal; D005260:Female; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D012016:Reference Values; D012680:Sensitivity and Specificity; D046509:Tissue Culture Techniques
chemical_list: D000809:Angiotensins; D000496:Alloxan