Thromboxane release from irradiated perfused rat lungs: role of oncotic agents.
Isolated lungs from 20 Gray (Gy) whole body irradiated rats were perfused with Krebs-Ringer bicarbonate plus 3% bovine serum albumin (KRB-BSA). The pulmonary effluent showed a 99% (p less than .05) increase in immunoassayable thromboxane B2 (iTXB2) release compared with non-irradiated lungs. Since both arachidonic acid and cyclooxygenase products bind to albumin, studies were performed to determine if omission or substitution of this protein oncotic agent would alter the radiation-induced increase in pulmonary iTXB2 release. Irradiated, isolated lungs perfused with media from which the BSA was omitted (KRB) did not demonstrate the radiation-induced increase in pulmonary iTXB2 release. Similarly, irradiated lungs perfused with media in which Dextran 70 (KRB plus 3% Dextran 70, KRB-Dextran 70) was substituted for BSA also did not show the radiation-induced increase in pulmonary effluent iTXB2 levels. These studies demonstrate the importance of including albumin as the oncotic agent in perfused organ systems when studying cyclooxygenase product release.
D000818:Animals; D003911:Dextrans / Q000494:pharmacology; D005720:Gamma Rays; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects*; D008297:Male; D010477:Perfusion; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D013929:Thromboxane B2 / Q000378:metabolism*; D014916:Whole-Body Irradiation
D003911:Dextrans; D012710:Serum Albumin, Bovine; D013929:Thromboxane B2