High-energy phosphates in heart, liver, kidney, and skeletal muscle of endotoxemic rats

Abstract

Endotoxemia can affect the storage of high-energy phosphates [ATP, creatine phosphate (CrP)] even in organs in which global blood flow does not fall. If a decrease in this storage is due to an inadequate oxygen supply-to-demand ratio, improving the perfusion should restore it. Therefore, in anesthetized endotoxemic rats we studied organ perfusion and the storage of high-energy phosphates of heart, liver, kidney, and skeletal muscle and measured the effects of improving cardiac output (CO) and organ blood flow with cardiostimulatory drugs [dopexamine (DX) and dobutamine (DB)]. Endotoxin (Escherichia coli O127.B8, 8 mg/kg) was infused from 0 to 60 min in three groups of anesthetized rats: one untreated (saline only) group (ES; n = 10), and two groups in which we infused DX (3 x 10(-8) mol.kg-1.min-1; n = 10) or DB (10(-7) mol.kg-1.min-1; n = 8) from 60 to 135 min. A fourth group served as time-matched controls (C; n = 8). Organ blood flows at 0 and 135 min (end of experiment) were measured with radioactive microspheres. In biopsies (at 135 min) we measured lactate, ATP, and CrP concentrations. Endotoxemia decreased CO (45% at 135 min; P < 0.05), which could be restored by DX and DB. Myocardial and skeletal muscle blood flow and ATP did not differ in the groups at 135 min. Hepatic and renal blood flow decreased in the ES group 44 and 52%, respectively (P < 0.05); DX restored the fall of hepatic and DB of renal blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)