Radiation-induced Changes in Production of Prostaglandins F 2α , E, and Thromboxane B 2 in Guinea Pig Parenchymal Lung Tissues

At 1 hour to 4 days after unilateral exposure of guinea pigs to a single dose (0 X 5, 1 X 5, or 3 X 0 Gy) of gamma-radiation, changes were detected in prostaglandin and thromboxane concentrations in parenchymal lung tissues. At 1-3 hours after exposure, tissue levels of PGF2 alpha, PGE, and thromboxane B2 were significantly elevated in animals receiving 3 X 0 Gy, with the magnitude of alteration revealing a radiation dose effect. By 24 hours, tissue prostaglandin and thromboxane levels returned to near control values. Lung tissue synthesis of prostaglandins in response to H-1 receptor stimulation by the exogenous addition of histamine revealed similar radiation dose effects. The carboxylic acid ionophore A23187, exogenously applied to lung tissues, revealed a transient peak of increased sensitivity to ionophore stimulation for TxB2 synthesis at 24 hours and for PGF2 alpha at 72 hours post-irradiation. The data suggest that significant alterations in prostaglandin and thromboxane concentrations in parenchymal lung tissues occur following irradiation, in a dose-dependent manner, and that altered responsiveness to H-1 receptor stimulation and divalent cation transport also occur.