Simultaneous quantitative analysis of prostaglandins and thromboxane after low-dose X irradiation

The appearance of prostaglandins and thromboxane in mouse serum after X irradiation was observed by simultaneous quantitative analysis using gas chromatography/mass spectrometry/selected ion monitoring with stable isotope dilution methods. Mice of two strains (C57BL/CN Jcl and BALB/c) showed similar responses to X irradiation. In C57BL/6N Jcl mice, 0.2 Gy irradiation elicited a significant increase in generation of prostanoids: Immediately after irradiation, the 6-keto PGF₁ α:TXB₂ ratio and the level of PGE₂ increased, after 20 min 6-keto PGF₁ α and PGE₂ increased, and after 4 h PGE₁ and PGE₂ increased. In BALB/c mice, generation of prostanoids was increased significantly immediately after irradiation (6-keto PGF₁ α, 6- keto PGF₁ α:TXB₂ ratio, PGF₂), and the increase was maintained from 20 min to 4 h (PGE₁, PGF₂) after 0.2 Gy irradiation. In C57BL/6N Jcl mice, a significant increase in production of 9α,11β-PGF₂ was observed at 20 min after irradiation. In BALB/c mice, a significant increase in 9α,11β-PGF₂ was seen immediately after irradiation and was maintained for 20 min. In C57BL/6N Jcl mice, the level of 8-epi PGF₂ α was clearly increased 4 h after 4 Gy irradiation. A slight and slow increase was also seen after 0.2 Gy irradiation. In BALB/c mice, 8-epi PGF₂ α was increased significantly at 20 min and 4 h after 4 Gy irradiation. These results show that 0.2 Gy irradiation stimulates production of prostanoids related to the inflammatory response in mice.