Intracavernosal kinetics of eicosanoids and endothelin during erection. Data from human and animal studies on intrapenile and systemic prostaglandins.

The release of mediator substances of the arachidonic acid cascade is closely related to the functional state of the endothelium. A significant lower prostacyclin/thromboxane A2 ratio in penile plasma of organogenic impotent patients in comparison to patients with psychogenic erectile dysfunction has been described in the literature. We observed the time-related liberation of prostacyclin, thromboxane A2 and the vasoactive peptide endothelin for 16 minutes of a drug-induced erection. We compared kinetics of patients with penile deviation and transsexualism, to patients suffering from severe organogenic impotence. We assessed the usefulness of the prostacyclin-to-thromboxane A2 ratio as a possible indicator of corporal degeneration. An animal model has been created to observe differences between rabbits under 100 days of standard diet alimentation, rabbits under cholesterol enriched diet and rabbits with hereditary hyperlipidemia type II A. Hyperlipidemia is suspected to be one possible factor causing organogenic impotence. Enzyme-immuno-assays were used for the determination of all substances. The systemic prostacyclin-to-thromboxane A2 ratio differed significantly between control rabbits and rabbits with hyperlipidemia. Prostacyclin, thromboxane A2 and endothelin in corpus cavernosum plasma showed a typical profile during spontaneous and drug-induced erection. A significant difference between groups of patients suffering from organogenic or psychogenic impotence could not be found. The value of the determination of the studied substances in differential diagnosis seems to be dubious.