Presentation Authors: M Ayodhia Soebadi, Leuven, Belgium, Thomas van den Broeck*, Lore Raets, Bert Brone, Koenraad van Renterghem, Hasselt, Belgium
Introduction: To investigate possible non genomic mechanisms mediating testosterone (T) induced relaxation in human corpus cavernosum tissue.
Methods: Human corpus cavernosum tissue samples were obtained after consent from men undergoing penile prosthesis implantation (n=46) for tissue strip contractility experiments. After precontraction with phenylephrine 10-5 we administered increasing doses of T. DHT, and androstenedione up to a maximum of 300 microM. Blockade of hydrogen sulfide and nitric oxide biosynthesis was studied. Fifteen minutes after addition of the different compounds, tissue relaxation was measured. Results are expressed as mean+/-SD. Statistical analysis was performed using unpaired t-test. All procedures and use of tissues were approved by the local ethical review board.
Results: At maximum concentration T relaxed precontracted tissues with 70.7 +/- 16.9 % (p = 0.003) compared to DMSO vehicle only. Androstenedione (p = 0.17) and DHT (p=0.09) resulted in no significant difference in relaxation compared to T. Response to T were not inhibited by N (G)-nitro-L-arginine methyl ester (p = 0.16), beta-cyanoalanine (p = 0.16), propargylglycine (p=0.34) and glibenclamide (p=0.73).
Conclusions: Previous research has suggested that relaxation effect of T on smooth muscle is mediated through non genomic mechanisms. We have shown that within the T biosynthesis pathway, T as well as precursor and derivative compounds produce relaxation. Blockade of nitric oxide, and hydrogen sulfide biosynthesis did not change the effect of T on relaxation. Because the effect is only seen at supraphysiological concentrations of T, further research is needed to elucidate the non-genomic mechanism of action of T on human CC tissue.