title: Biological half-life of prostacyclin and 6-oxo-PGF1 alpha levels in plasma of patients with colonic cancer.
abstract: Prostaglandins have been shown to play a central role in the formation of cancer. The synthesis of prostacyclin and its bioavailability may be an important local determinant for metastasis. As the amount of the biologically active substance is dependent in part on the half-life (T/2) we examined the question as to whether the T/2 of prostaglandin I2 (PGI2) is altered in patients suffering from colonic cancer at various stages of the disease. In addition, the influence of various therapeutic regimens was investigated. In 58 patients with various stages of colonic cancer no significant difference in PGI2-T/2 could be detected. No significant difference could be found before (10, 11 +/- 1, 9 min) and after (10, 03 +/- 1, 8 min) tumor resection, before (9, 89 +/- 1, 5 min) and after 10, 35 +/- 1,8 min) chemotherapy, before (10, 36 +/- 1, 5 min) and after (10, 89 +/- 2, 31 min) irradiation as well as before (8, 86 +/- 1, 9 min) and after (9, 07 +/- 1, 2 min) tumor resection at least 4 to 6 years ago. In 14 healthy people PGI2-T/2 (10, 05 +/- 2, 1 min) did not differ significantly. In all the 58 patients the plasma levels of 6-oxo-PGF1 alpha, the stable derivative of PGI2 were measured. As compared to healthy controls (less than 1 pg/ml) the actual 6-oxo-PGF1 alpha values of patients with colonic cancer were significantly increased. However, no correlation to the T/2 of PGI2 (r between 0, 03 and 0, 21, n.s.) in plasma in vitro could be discovered. After curative tumor resection and after chemotherapy the plasma levels of 6-oxo-PGF1 alpha were significantly lower than before. The data suggest that in patients suffering from colonic cancer the speed of degradation of PGI2 is not a key determinant in local hemostatic dysregulation favouring early metastasis. However, PGI2 or its stable derivatives may be involved in the development of colonic cancer.
mesh_terms: D015121:6-Ketoprostaglandin F1 alpha / Q000097:blood*; D000328:Adult; D000368:Aged; D003110:Colonic Neoplasms / Q000097:blood* / Q000628:therapy; D011464:Epoprostenol / Q000097:blood*; D005260:Female; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging
chemical_list: D015121:6-Ketoprostaglandin F1 alpha; D011464:Epoprostenol