Infection is a major complication of patients with diabetes, and endotoxemic shock is a serious complication during sepsis. The purpose of this study was to determine whether the action of bacterial lipopolysaccharide (LPS) on vasocontractility is altered in diabetic vessels. Diabetes was induced in 10-week-old Wistar rats by an intraperitoneal injection of streptozotocin. LPS-induced increase in cGMP (cyclic guanosine 3',5'-monophosphate) level was lower in aortae from streptozotocin-induced hyperglycemic (diabetic) rats than in those from vehicle-injected control rats, while LPS-induced nitric oxide production was not different in the diabetic and control aortae. Phenylephrine-induced contraction of diabetic aortae was lower than that of the control aortae. LPS treatment resulted in depression of contractile response to phenylephrine in both diabetic and control aortae, and the degree of depression was much lower in diabetic aortae. Treatment with N monomethyl l-arginine (l-NMMA) prevented diminution of phenylephrine-induced contraction of the aortae after LPS stimulation, and the degree of the preventive effect by l-NMMA was significantly lower in diabetic aortae than in the control aortae. Protein expression of inducible nitric oxide synthase detected by Western blot analysis was not different in the diabetic and control aortae. The decrease in cGMP production after LPS stimulation in diabetic aortae was not prevented by treatment of the aortae with superoxide dismutase but was partially prevented by that with Tiron (4,5-dihydroxy-1,3-benzene disulfonic acid), a cell-permeable scavenger of reactive oxygen species. These results suggest that LPS-induced depression of vasocontractility is attenuated in diabetic aortae due to a decrease in nitric oxide-stimulated cGMP production, probably resulting from increased inactivation of inducible nitric oxide by excessive intracellular oxidative stress. It is concluded that contractility of aortae from streptozotocin-induced hyperglycemic rats may be less affected by LPS during endotoxemia.

In rat alveolar macrophages, LPS-induced expression of COX-2 and iNOS is mediated by ERK MAPK but not by p38 MAPK. Acute ethanol administration to rats attenuates induction of both COX-2 and iNOS in alveolar macrophages by inhibiting phosphorylation of ERK.

Effects of ethanol in vitro on inducible nitric oxide (NO) production in RAW 264.7 macrophages were investigated. Adding ethanol (100-600 mM) to the incubation medium simultaneously with lipopolysaccharide (LPS) concentration-dependently inhibited LPS-induced NO production without being cytotoxic. This inhibitory effect of ethanol on NO production was almost abolished when ethanol was added to the medium 12 h after the start of incubation with LPS, implying that ethanol inhibits the induction of inducible NO synthase (iNOS). Both LPS-induced protein and mRNA expression of iNOS were inhibited by ethanol (100-600 mM) concentration-dependently. LPS-induced activation of signal transducer and activator of transcription-1 (STAT-1) was inhibited by ethanol (100-400 mM). On the other hand, LPS-induced translocation of nuclear factor-kappaB (NF-kappaB) was not affected significantly by 100-600 mM ethanol. When cells were exposed to ethanol for 72 h before LPS stimulation, the inhibitory effect of ethanol on subsequent NO production was significantly attenuated compared with that in control cells pretreated with vehicle for 72 h, suggesting the development of tolerance to the inhibitory action of ethanol. These results suggest that ethanol inhibits inducible NO production, probably by inhibiting STAT1 activation. Tolerance to this inhibitory action of ethanol is produced after chronic exposure.

No abstract

The purpose of the present study was to determine the proteins that bind to acetophenones in the liver. Immobilized p-hydroxyacetophenone (p-HAP) was used as a ligand of affinity chromatography. Analysis using sodium dodesyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that five polypeptides in the liver cytosolic fraction specifically bound to the p-HAP matrix. These polypeptides were digested with Lys-specific protease and used to generate peptide maps by reversed-phase high-performance liquid chromatography. Consequently, identification from a data base of protein sequences revealed that the five polypeptides were glycogen phosphorylase, cytosolic aldehyde dehydrogenase, adenosine kinase, class I alcohol dehydrogenase and glutathione S-transferase A2. In addition to p-HAP, acetylsalicylic acid also displayed a prominent ability to elute these five enzymes from the p-HAP affinity column loaded with the cytosolic fraction of the liver. Thus, p-HAP has affinities to the above liver enzymes and is a useful ligand for analysis of them.