Studies on erectile dysfunction (ED) have revealed a relationship between smooth muscle atrophy and the accumulation of collagen in the corpus cavernosum (CC). Transforming growth factor ß1 (TGF ß1) is a cytokine which has been proposed to be involved in the fibrotic process in the CC. We aimed to evaluate the course of TGF ß1 in the systemic and cavernous blood of 17 healthy males through different phases of the sexual arousal response (exemplified by the penile conditions flaccidity, tumescence, rigidity and detumescence). An enzyme-linked immunoassay was used to measure the concentration of TGF ß1 (ng/ml) in both the systemic and cavernous blood at the stages of flaccidity, tumescence and detumescence. TGF levels were significantly higher in the cavernous compartment than in the systemic blood. A linear decrease was evident in the cavernous blood when the flaccid penis became tumescent (24.3 ± 14.5 to 13.9 ± 6.5) and rigid (to 8.7 ± 3.1). At detumescence, TGF increased to 18.3 ± 10.4. In contrast, the levels in the systemic circulation remained unchanged. The results are in support of the hypothesis that the concentration of TGF ß1 in the CC is regulated by adequate blood flow and oxygenation.
- penile erection
- sexual arousal
- transforming growth factor ß1 (TGF ß1)