Accession Number : ADA186556

Title :   Thromboxane-Mediated Injury Following Radiation.

Descriptive Note : Annual rept. 1 Sep 85-17 Jun 86, Final rept. 15 Jan 84-17 Jun 86,

Corporate Author : GEORGETOWN UNIV WASHINGTON D C

Personal Author(s) : Kot, Peter A

PDF Url : ADA186556

Report Date : 18 Jun 1986

Pagination or Media Count : 39

Abstract : Previous studies demonstrated an increased in vivo and in vitro release of immunoreactive thromboxane B2 (TXB2) four hours after 20.0 Gy whole body irradiation. This radiation-induced increase in TXB2 release was of extrarenal origin. This report confirms that whole body ionizing radiation exposure results in an increased pulmonary TXB2 release. Since radiation exposure is associated with an increased release of TXB2, the present studies sought to determine if tissue responsiveness was altered to this cyclooxygenase product. Rats were anesthetized (30 mg/kg sodium pentobarbital, i.p.) and exposed to 20.0 Gy whole body gamma irradiation. The effect of the radioprotectant, WR2721, on the radiation-induced depression in vascular reactivity was assessed next. The release of TXB2 from the pulmonary bed of irradiated animals was determined. These results indicate the importance of a plasma-like perfusate in studying cyclooxygenase product release from isolated organs. The data also show that radiation exposure will depress vascular reactivity to the TXA2 mimic, U46619. This radiation-induced alteration in vascular reactivity was preventable by treatment of the animals with the radioprotectant, WR2721, prior to irradiation. These results suggest that the altered release of TXB2 seen following lethal doses of gamma radiation may have both physiological ramifications and pharmacological applications.

Descriptors :   *RADIATION EFFECTS, *BIOCHEMISTRY, *RADIOPROTECTIVE AGENTS, CARDIOVASCULAR SYSTEM, GAMMA RAYS, IN VITRO ANALYSIS, IN VIVO ANALYSIS, IRRADIATION, ISOLATION, LETHAL DOSAGE, ORGANS(ANATOMY), PHARMACOLOGY, RATS, REACTIVITIES, RELEASE, WHOLE BODY IRRADIATION, EXPOSURE(PHYSIOLOGY), LUNG

Subject Categories : Radiobiology
      Biochemistry
      Pharmacology

Distribution Statement : APPROVED FOR PUBLIC RELEASE