It has been suggested that penile hypercoagulability predisposes to aging penile vascular changes and impotence, and that elevated thromboxane A2 (TXAZ) during erection may contribute to hyper-coagulability and atherosclerosis. Since the ratio of prostacylin (PGI2) concentration to TXAZ concentration is fixed, an imbalance between TXAZ and PGI2 may be a factor to initiate vascular diseases
r: and decreased blood flow.
The present study was designed to asses the usefulness of PGI2/TXAZ ratio´ in penile blood dur-
r. .
ing erection for diagnosis of arteriogenic impotence.
Fifty patients of 13 psychogenic, 30 arteriogenic and 7 venogenic impotences were investigated. The underlying causes of the arteriogenic impotences were diabetes mellitus in 9, trauma in 5, hypertension in 6 and undetermined in 10.
Production of PGI2 and TXAZ in cavernosal blood of the papaverine induced erected penis was determined by radio-immunoassay of their stable hydrolysis products, 6-keto prostaglandin F,a (PGFa) and thromboxane B2(TXBZ), respectively.
The results were as follows:
1. Mean value SD of PGF,a was 75.06 22.74 ng/ml in psychogenic, 55.39 + 26.08 ng/ml in arteriogenic and 90.97 33.54 ng/ml in venogenic impotence.
2. Mean value SD of TXBZ was 56.54 35.76 ng/ml in psychogenic, 154.41 192.58 ng/ml in arteriogenic and 110.89 75.08 ng/ml in venogenic impotence.
3. Mean SD of PGI2/TXA2 ratio was 1.81 1.16 in psychogenic; 0.77 0.54 in arteriogenic and 1.30 1.05 in venogenic impotence. There was significant difference (p<0.01) of the ratio between psychogenic and arteriogenic impotence but no significant difference between psychogenic and venogenic impotence. The ratio according to the underlying causes of the arteriogenic impotences was not significantly different.
4. PGI2%TXA2 ratio for arteriogenic impotence was also significantly (p<0.01) lower than that for psychogenic impotence when compared in 3. age groups (20-29, 30-39 and 40-49 years) in order to take consideration into age dependence of the ratio.
In conclusion, PGI2/TXAZ ratio seems to be useful to diagnose the arteriogenic impotence.
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