Effect of radiation on prostaglandin production by human bowel in vitro

The effect of gamma irradiation on the production of prostaglandins by human colon was investigated. Squares of tissue in organ culture dishes were irradiated with 500, 1000, or 2500 rad in single applications. Tissues that were not irradiated served as controls. After treatment the tissues were superfused and prostaglandin concentrations in the effluent fluid were determined. The rates of production of prostaglandins E 2 and F 2α by irradiated tissues were significantly lower ( p < 0.05) than those of nonirradiated tissues. Neither the release of lactate dehydrogenase nor the rate of production of 13,14-dihydro-15-keto-prostaglandin F 2α were increased in the irradiated samples, suggesting that neither decreased cell viability nor increased prostaglandin metabolism accounted for the decreased prostaglandin production rates. We conclude that irradiation of the human colon in vitro results in an acute inhibition of prostaglandin synthesis. The cytoprotective nature of prostaglandins is discussed with regard to the possible pathophysiological significance of these findings.