Prostacyclin production in cultured endothelial cells is highly sensitive to low doses of ionizing radiation

In an attempt to detect if low doses of ionizing radiation affect the physiological function of blood vessels, the effect of prostacyclin production was examined using cultured endothelial cells. Irradiation with 5 cGy suppressed the production to 53% of the levels in unirradiated control cells. The PGI₂ production decreased with an increase in the dose, showing a maximal decrease at 100 cGy without further decrease at 200 cGy. The suppressive effect lasted for 15 min after irradiation and disappeared later. Preincubation with αtocopherol abrogated the suppressive effect completely, although preincubation with ascorbic acid showed little effect. These results suggest that low dose irradiation inhibits the prostacyclin production by changing the cellular membranes transiently.