Background: We have reported that administration of recombinant human interleukin (IL)-1β induced circulatory shock in rabbits by causing overproduction of vasodilating prostaglandin(s) and simultaneously impaired oxygen metabolism by causing an abnormal dependence of oxygen consumption (VO2) on oxygen delivery (DO2). The present study was carried out to compare the effect of administration of exogenous PGE1 with that of IL-1β on oxygen metabolism. Methods: Sixteen rabbits were assigned to one of three groups and given a single injection of 10 μg/kg IL-1β (IL-1β group, n = 5), continuous infusion of 1 μg/kg/min PGE1 (PGE1 group, n = 6), or saline (control group, n = 5). All rabbits were subjected to stepwise cardiac tamponade to decrease DO2 by inflating a balloon placed into the pericardial sac. The VO2/DO2 relation was analyzed by the dual-line method. Results: Both IL-1β and PGE1 decreased the baseline value of mean arterial pressure by approximately 25% without inducing significant alteration of the cardiac index. With respect to the VO2/DO2 relation, the slope of the supply-independent line was significantly increased in the IL-1β group (y = 0.13x + 6.4), but not in the PGE1 group (y = 0.01x + 10.0) compared to that in the control group (y = 0.05x + 8.7). Conclusion: These results indicate that simple vasodilation and hypotension induced by administration of PGE1 are insufficient to account for the abnormal oxygen metabolism induced by IL-1β.
Background: We have reported that administration of recombinant human interleukin (IL)-1β induced circulatory shock in rabbits by causing overproduction of vasodilating prostaglandin(s) and simultaneously impaired oxygen metabolism by causing an abnormal dependence of oxygen consumption (VO2) on oxygen delivery (DO2). The present study was carried out to compare the effect of administration of exogenous PGE1 with that of IL-1β on oxygen metabolism. Methods: Sixteen rabbits were assigned to one of three groups and given a single injection of 10 μg/kg IL-1β (IL-1β group, n = 5), continuous infusion of 1 μg/kg/min PGE1 (PGE1 group, n = 6), or saline (control group, n = 5). All rabbits were subjected to stepwise cardiac tamponade to decrease DO2 by inflating a balloon placed into the pericardial sac. The VO2/DO2 relation was analyzed by the dual-line method. Results: Both IL-1β and PGE1 decreased the baseline value of mean arterial pressure by approximately 25% without inducing significant alteration of the cardiac index. With respect to the VO2/DO2 relation, the slope of the supply-independent line was significantly increased in the IL-1β group (y = 0.13x + 6.4), but not in the PGE1 group (y = 0.01x + 10.0) compared to that in the control group (y = 0.05x + 8.7). Conclusion: These results indicate that simple vasodilation and hypotension induced by administration of PGE1 are insufficient to account for the abnormal oxygen metabolism induced by IL-1β.