title: Testosterone regulates RhoA/Rho-kinase signaling in two distinct animal models of chemical diabetes.
abstract: BACKGROUND
  The contractile RhoA/Rho-kinase (ROCK) signaling pathway is upregulated in penile tissue in animal models of experimental diabetes and has been proposed to contribute to diabetes-related erectile dysfunction (ED).
  
  
  OBJECTIVE
  To investigate the effect of testosterone (T) on the RhoA/ROCK signaling in diabetes.
  
  
  METHODS
  We used two distinct animal models of chemical diabetes (alloxan-induced in the rabbit and streptozotocin-induced in the rat) with or not T supplementation.
  
  
  METHODS
  The effect of diabetes and T supplementation on RhoA/ROCK signaling was evaluated as responsiveness to the selective ROCK inhibitor Y-27632 either by "in vitro" contractility study (diabetic rabbit) or "in vivo" as erectile response elicited by intracavernous injections (diabetic rats). RhoA/ROCK gene and protein expression were also analyzed.
  
  
  RESULTS
  In both models, hypogonadism was observed, characterized by reduced T plasma level and androgen-dependent accessory glands atrophy. Diabetic animals showed a significant increase in responsiveness to increasing concentrations of Y-27632. T substitution (30 mg/kg, weekly) completely prevented hypogonadism and diabetes-induced penile hypersensitivity to Y-27632. To test whether this effect was due to a T-dependent regulation of RhoA/ROCK gene expression, we measured RhoA/ROCK mRNA. Both isoforms of ROCK (ROCK1/ROCK2) were analyzed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) in rat penile samples. We found that ROCK1 mRNA was significantly increased (P < 0.05) in penile tissues from diabetic animals and maintained at the control values by T, as also confirmed by semiquantitative RT-PCR in rabbit. Conversely, RhoA and ROCK2 mRNA expression was not influenced either by diabetic condition or by T administration. Accordingly, ROCK1 protein expression, as evaluated by Western blot and immunohistochemistry analysis, was increased in penile samples from diabetic animals and normalized by T.
  
  
  CONCLUSIONS
  Our data further support the hypothesis that the overexpression of RhoA/ROCK signaling contributes to diabetes-related ED. Moreover, treating hypogonadism in course of diabetes may maintain erectile function also by normalizing RhoA/ROCK pathway upregulation.
authors.affiliation: Andrology Unit, Florence, Italy.
authors.forename: Linda
authors.initials: L
authors.lastname: Vignozzi
authors.affiliation: Andrology Unit, Florence, Italy.
authors.forename: Annamaria
authors.initials: A
authors.lastname: Morelli
authors.affiliation: Interdep. Laboratory of Functional and Cellular Pharmacology of Reproduction, Departments of Pharmacology and Clinical Physiopathology, University of Florence, Florence, Italy.
authors.forename: Sandra
authors.initials: S
authors.lastname: Filippi
authors.affiliation: Department of Anatomy, Histology and Forensic Medicine, University of Florence, Florence, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ambrosini
authors.affiliation: Andrology Unit, Florence, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Mancina
authors.affiliation: Endocrinology Unit, Department of Clinical Physiopathology, Center for Research, Transfer and High Education DENOTHE, University of Florence, Florence, Italy.
authors.forename: Michaela
authors.initials: M
authors.lastname: Luconi
authors.affiliation: Andrology Unit, Florence, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Mungai
authors.affiliation: Department of Anatomy, Histology and Forensic Medicine, University of Florence, Florence, Italy.
authors.forename: Gabriella Barbara
authors.initials: GB
authors.lastname: Vannelli
authors.affiliation: Andrology Unit, Florence, Italy.
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Zhang
authors.affiliation: Endocrinology Unit, Department of Clinical Physiopathology, Center for Research, Transfer and High Education DENOTHE, University of Florence, Florence, Italy.
authors.forename: Gianni
authors.initials: G
authors.lastname: Forti
authors.affiliation: Andrology Unit, Florence, Italy. Electronic address: m.maggi@DFC.UNIFI.IT.
authors.forename: Mario
authors.initials: M
authors.lastname: Maggi
mesh_terms: D000496:Alloxan; D000577:Amides / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000150:complications / Q000378:metabolism*; D004195:Disease Models, Animal; D007172:Erectile Dysfunction / Q000201:enzymology* / Q000209:etiology / Q000517:prevention & control*; D007006:Hypogonadism / Q000209:etiology; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D010413:Penis / Q000187:drug effects / Q000201:enzymology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013311:Streptozocin; D013739:Testosterone / Q000378:metabolism* / Q000494:pharmacology*; D015854:Up-Regulation; D054460:rho-Associated Kinases
chemical_list: D000577:Amides; D047908:Intracellular Signaling Peptides and Proteins; D011725:Pyridines; C108830:Y 27632; D013739:Testosterone; D013311:Streptozocin; D000496:Alloxan; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases