Receptor subtype mediating the action of circulating endothelin on glucose metabolism and hemodynamics in perfused rat liver

The subtype of endothelin receptor that mediates metabolic and hemodynamic effects of circulating endothelin was explored using perfused rat liver. Infusion of endothelin (ET)-1 or ET-3 into the portal vein at a concentration of 0.3 nM increased glucose and lactate output and decreased perfusion flow, although ET-3 was less effective than ET-1. The metabolic effects of ET-1 were observed even under costant-flow perfusion. Infusion of either sarafotoxin S6b or S6c, an ET(A)- or ET(B)-receptor agonist, mimicked the actions of ET-1 to an equal extent. The flow reduction and glucose production induced by ET-1 were partly attenuated by the ET(A)-receptor antagonist BQ485. By contrast, ET(B)-receptor antagonist BQ788 enhanced glucose production caused by ET-1 and ET-3 without affecting the hemodynamic change. The effects of ET-1 and ET-3 were almost totally inhibited by the combination of BQ485 and BQ788. These results suggest that both ET(A) and ET(B) receptors are involved in the metabolic and hemodynamic effects of circulating endothelin in rat liver, while the ET(A)-receptor-mediated action appears to be dominant.

Role of the sympathetic nervous system and insulin in enhancing glucose uptake in peripheral tissues after intrahypothalamic injection of leptin in rats

Our previous study demonstrated that microinjection of leptin into the ventromedial hypothalamus (VMH) dramatically increased glucose uptake in the heart, brown adipose tissue (BAT), and skeletal muscles, but not in white adipose tissue (WAT) in conscious unrestrained rats, as assessed in vivo by the 2-[3H]deoxyglucose method. Here we examined the role of the sympathetic nervous system and insulin in enhanced glucose uptake by tissues after hypothalamic leptin injection. Pretreatment with guanethidine significantly suppressed the increased glucose uptake by the tissues in response to leptin injected into the VMH, whereas bilateral adrenal demedullation had no significant effect. Treatment with propranolol but not phenoxybenzamine also decreased significantly enhanced glucose uptake by the tissues. We further examined the interaction of the effects of hypothalamic leptin and insulin administered peripherally by clamping the glucose concentrations at a constant level. When leptin was injected into the VMH and a maximal dose of insulin was administered intravenously, the rates of glucose uptake by the heart, BAT, and skeletal muscles, but not by WAT, markedly increased beyond the values reached by insulin stimulation alone. Surgical sympathetic denervation of BAT abolished the enhancement of glucose uptake in this tissue, decreasing to the level stimulated by insulin alone. These results appear to indicate that leptin in the hypothalamus enhances glucose uptake in certain peripheral tissues through mediation of a beta-adrenergic mechanism for the sympathetic nerves innervating the tissues and that central leptin and peripheral insulin have a synergistic role in augmenting tissue glucose uptake.

Little benefit from mild hypothermia therapy for severely head injured patients with low intracranial pressure

OBJECT

This study was performed to determine whether mild hypothermia therapy is essential for the treatment of severely head injured patients in whom intracranial pressure (ICP) can be maintained below 20 mm Hg by using conventional therapies.

METHODS

Sixteen consecutive severely head injured patients fulfilled the following criteria: the patient's ICP was maintained below 20 mm Hg by using fluid restriction, hyperventilation, and high-dose barbiturate therapy; and the patient had a Glasgow Coma Scale score of 8 or less on admission. After conventional therapies had been applied, the patients were divided randomly into two groups: the mild hypothermia group (HT group; eight patients) and the normothermia group (NT group; eight patients). The HT group received mild hypothermia (intracranial temperature 34 degrees C) therapy for 48 hours followed by rewarming at 1 degree C per day for 3 days, whereas the NT group received normothermia (intracranial temperature 37 degrees C) therapy for 5 days. Specimens of cerebrospinal fluid (CSF) taken from an intraventricular catheter every 24 hours were analyzed for the presence of excitatory amino acids ([EAAs] glutamate, aspartate, and glycine) and cytokines (tumor necrosis factor-alpha, interleukin [IL]-1beta, IL-6, IL-8, and IL-10). The two groups did not differ significantly in patient age, neurological status, or level of ICP. There were no significant differences in daily changes in CSF concentrations of EAAs and cytokines between the two groups. The incidence of pneumonia was slightly higher in the HT group compared with the NT group (p = 0.059). The incidence of diabetes insipidus associated with hypernatremia was significantly higher in the HT group compared with that in the NT group (p < 0.01). The two groups did not differ with respect to their clinical outcomes.

CONCLUSIONS

The authors recommend normothermia therapy for the treatment of severely head injured patients in whom ICP can be maintained at lower than 20 mm Hg by using conventional therapies, because mild hypothermia therapy does not convey any advantage over normothermia therapy in such patients.

L-Glutamate and insulin enhance glycogen synthesis in cultured astrocytes from the rat brain through different intracellular mechanisms

The effects of L-glutamate and insulin on glycogen synthesis in astrocytes were examined. L-Glutamate and insulin both stimulated glycogen synthesis in primary cultures of rat astrocytes in a dose-dependent manner, as measured by the incorporation of 14C from [14C]glucose into glycogen. D-Aspartate also increased the incorporation of 14C into glycogen. When insulin and L-glutamate were added together, the glycogen synthesis as well as glycogen content of the cells was additively increased. Wortmannin, an inhibitor of phosphatidylinositol 3-kinase, had little effect on glycogen synthesis induced by L-glutamate, whereas it suppressed the insulin-induced glycogen synthesis. These results suggest that the insulin- and L-glutamate-induced glycogen syntheses are mediated by different intracellular mechanisms. In fact, insulin stimulated the conversion of glycogen synthase b to glycogen synthase a, which was suppressed by wortmannin. L-Glutamate and D-aspartate, however, did not increase the level of glycogen synthase a activity. By contrast, L-glutamate increased 2-deoxy-D-[3H]glucose uptake by the astrocytes, whereas insulin did not affect the uptake. These results suggest that insulin stimulates glycogen synthesis in astrocytes by activating glycogen synthase, which is dependent on a wortmannin-sensitive signaling pathway. L-Glutamate, however, enhances the glucose uptake, which contributes to the increase in glycogen synthesis in the cells.

Granulocyte colony-stimulating factor ameliorates life-threatening infections after combined therapy with barbiturates and mild hypothermia in patients with severe head injuries

OBJECTIVE

The objective of this study was to clarify the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration on infections in patients with severe head injuries after combined therapy with high-dose barbiturates and mild hypothermia.

PATIENTS AND METHODS

Since 1996, we have administered rhG-CSF to eight patients with severe head injuries for 5 days (group G). Their treatment results were compared with those of 22 patients cared for earlier without rhG-CSF treatment (group N). All patients in both groups met the criteria of total leukocyte count (TLC) less than 5,000/mm3, C-reactive protein (CRP) over 10 mg/dL, and the presence of an infectious complication. Changes in the TLC, CRP, respiratory index, intracranial pressure, and infectious condition were evaluated in both groups. In addition, the nucleated cell count and differentiation from bone marrow aspiration, neutrophil functions, serum concentrations of interleukin-6, and plasma concentration of leukocyte elastase were evaluated in group G.

RESULTS

In group G, TLC, nucleated cell count, and neutrophil functions significantly increased, whereas CRP, respiratory index, and interleukin-6 decreased reciprocally. There was no deterioration of intracranial pressure and leukocyte elastase. Consequently, seven of the eight patients in group G recovered from life-threatening infections, and none of the eight patients died. However, in group N, CRP and respiratory index remained high and TLC did not increase as much as it did in group G. Infections continued after 5 days in 17 of the 22 patients, 7 of whom died from severe infections during hospitalization.

CONCLUSION

Administration of rhG-CSF ameliorated life-threatening infections without causing lung injury or increasing brain swelling in patients with severe head injuries who were treated with combined therapy involving high-dose barbiturates and mild hypothermia.

Priming, second-hit priming, and apoptosis in leukocytes from trauma patients

BACKGROUND

Polymorphonuclear leukocytes (PMNL) play important roles in both host defenses and systemic inflammatory responses after insults. The objectives of this study are to examine the serial changes in PMNL priming and apoptosis in severely injured patients and to evaluate the impact of second hits on primed PMNL function and systemic vascular endothelial damage.

METHODS

Twenty-four severely injured patients (mean Injury Severity Score, 31.1 +/- 9.7) were included. Infections were seen as second hits after trauma in seven patients. Oxidative activity, phagocytosis, and apoptosis of PMNL from serial blood samples were measured by flow cytometry. Oxidative activity with no stimulus and with formylmethionyl-leucyl-phenylalanine (FMLP) were analyzed as the priming index and FMLP response, respectively. Interleukin (IL)-6, IL-10, PMNL elastase, and thrombomodulin concentrations in blood were also measured before and after the second hit.

RESULTS

The PMNL priming index was elevated from days 2 to 13, especially days 2 to 5 after injury. FMLP response was enhanced from days 2 to 21 after injury. Apoptosis of PMNL was inhibited for as long as 3 weeks after injury. Infections as second hits after trauma enhanced both the priming index and the FMLP response within 24 hours after diagnosis of infection and increased serum IL-6 concentrations. However, serum thrombomodulin levels were not affected by second hits. All patients with second hits survived.

CONCLUSION

Severe trauma stimulated acute-phase priming in PMNL and inhibited apoptosis. Infections after trauma induced second-hit priming in PMNL, but the unchanged serum levels of thrombomodulin suggest that priming per se may not cause systemic vascular endothelial damage.

Complex hprt deletion events are recovered after exposure of human lymphoblastoid cells to high-LET carbon and neon ion beams

Hypoxanthine phosphoribosyltransferase gene (hprt) mutations were induced in human TK-6 lymphoblastoid cells by irradiation at a linear energy transfer (LET) of 250 or 310 keV/micron for carbon and neon ions, respectively. At such a high level of LET, ions will lose most of their total energy and stop shortly after passing through the cell. The hprt mutations were analyzed by multiplex PCR, long-PCR and DNA sequencing of both genomic and cDNA. Over half of the C ion-induced hprt mutations (10 of 19) were point mutations, in contrast to 15% of the mutations induced by Ne ions (three of 20). The remaining 47 and 85% of the C and Ne ion-induced mutants, respectively, are deletion events. The latter events include three complex losses of multiple non-contiguous exon regions in both ion irradiation collections. We note that mutations involving the exon 6 region are frequent in the Ne ion collection: all three of the complex events retained the exon 6 region with flanking deletion of sequence and three other mutants involved deletion of this region. It may be concluded that these high-LET C and Ne ion irradiations produce different mutational spectra.

STS-95 Space Experiments (plants and cell biology)

We report the outline of Space Experiments conducted on Space Shuttle (STS-95) launched in autumn of 1998. In this STS-95 mission, Japanese astronaut Dr. Chiaki Mukai achieved her 2nd space flight and conducted a part of 82 space experiments including Japanese experiments. US astronaut Senator John Glenn also achieved his second space flight, 36 years after his first space flight. Senator Glenn was a leader of the original (the first) 7 US astronauts and very famous in US because he succeeded US first orbital space flight around the earth. NASDA had started the project of space experiment using STS-95 at the summer of 1997, therefore we had only one year for the all preparation Yamashita, et al. Biological Sciences in Space, Vol.12 No.3(1998). Scientific results will be reported by investigators, therefore we report here how we had been developing the space experiment plan, on board operation procedure and ground operations including ground control experiments about four plant experiments and one cell biology experiment.

Morbidity and mortality of hospitalized patients after the 1995 Hanshin-Awaji earthquake

The objective of this study was to provide an overview of the morbidity and mortality of hospitalized patients during the Hanshin-Awaji earthquake. Medical records of 6,107 patients admitted to 95 hospitals (48 affected hospitals within the disaster area and 47 back-up hospitals in the surrounding area) during the initial 15 days after the earthquake were analyzed retrospectively. Patient census data, diagnoses, dispositions, and prognoses were considered. A total of 2,718 patients with earthquake-related injuries were admitted to the 95 hospitals included in our survey, including 372 patients with crush syndrome and 2,346 with other injuries. There were 3,389 patients admitted with illnesses. Seventy-five percent of the injured were hospitalized during the first 3 days. In contrast, the number of patients with illnesses continued to increase over the entire 15-day period after the earthquake. The mortality rates were 13.4% (50/372), 5.5% (128/2,346), and 10.3% (349/3,389) associated with crush syndrome, other injuries, and illness, respectively. The overall mortality rate was 8.6% (527/6,107 patients). Morbidity as well as mortality rates increased with age in patients with both injuries and illnesses. In the initial 15-day period, there was an unprecedented number of patients suffering from trauma, and they converged upon the affected hospitals. Subsequently an increased incidence of illness was observed. This survey underscores the need for adequate disaster response in such an urban situation.

Microinjection of leptin into the ventromedial hypothalamus increases glucose uptake in peripheral tissues in rats

We studied the effects of microinjection of leptin into the ventromedial hypothalamus (VMH) and lateral hypothalamus (LH) on glucose uptake in peripheral tissues in unanesthetized rats. The rate of glucose uptake was assessed in vivo by 2-[3H]deoxyglucose incorporation. Single injection of leptin into VMH increased glucose uptake in brown adipose tissue (BAT), heart, skeletal muscles, and spleen but not in white adipose tissue or skin. On the other hand, microinjection of leptin into LH had little effect on glucose uptake in those tissues. The plasma concentrations of glucose and insulin were unaltered by intrahypothalamic injection of leptin into either VMH or LH. Among skeletal muscles, the increase in glucose uptake induced by intrahypothalamic injection of leptin was greater in the soleus than in the extensor digitorum longus. Likewise, the increased glucose uptake in the gastrocnemius in response to leptin was more prominent in the red part than in the white part of the tissue. When surgical sympathetic denervation of the interscapular BAT was performed, the enhanced glucose uptake by BAT in response to intrahypothalamic leptin was completely suppressed. These findings suggest that intrahypothalamic injection of leptin preferentially increases glucose uptake by some peripheral tissues through activation of the VMH-sympathetic (or its neighboring medial hypothalamus-sympathetic) nervous system, thereby contributing to the maintenance of energy balance.

Does growth hormone augment brain edema caused by brain injury? A study with a freeze brain injury model in the rat

OBJECTIVE

Because of the known sodium and water retention associated with growth hormone (GH) therapy, it is crucial to evaluate the safety of GH after brain injury. To clarify this issue, we investigated whether GH affects brain edema in a rat brain freeze-injury model.

METHODS

Male Wistar rats (n = 29) were divided into four groups according to the substance injected (GH vs. normal saline) and whether the brain was injured or not. The subcutaneous injections of GH (0.8 IU/kg) or saline were given 24 hours apart. In the injury groups, after the second injection, an aluminum rod (4-mm diameter) cooled to -50 degrees C was placed on the exposed dura mater in the right parietal region for 4 minutes, under anesthesia. At 4 hours after the insult, brain and skeletal muscle were excised and their water content was measured by drying.

RESULTS

Freeze injury of the brain caused an increase in water and sodium content in skeletal muscle. GH injection augmented this edema in skeletal muscle. Freeze injury of the brain also caused an increase in water and sodium content in the injured hemisphere of the brain. GH injection did not exacerbate this edema in injured brain tissue. Neither freeze injury nor GH injection caused brain edema in the noninjured hemisphere or in the cerebellum.

CONCLUSION

GH administration did not augment brain edema caused by brain injury in our model.

Aggravating action of zymosan on acute liver damage in perfused liver of rats treated with D-galactosamine

To study the role of Kupffer cells in the aggravation of liver injury, effects of zymosan on acute liver damage were explored using perfused livers of rats 24 h after intraperitoneal injection of D-galactosamine (800 mg/kg). The leakage of lactate dehydrogenase and aspartate aminotransferase into the effluent was used to indicate acute liver damage. Infusion of zymosan (30 microgram/ml) into the portal vein rapidly increased the leakage of lactate dehydrogenase and aspartate aminotransferase from galactosamine-treated liver with decreased perfusion flow. Pretreatment of animals with gadolinium, which diminished an immunostaining of resident macrophages in the injured liver, significantly attenuated the flow reduction induced by zymosan, whereas it did not affect the increases in enzyme leakage. Infusions of PGF2alpha, PGE2, and leukotriene D4, the eicosanoids mainly produced by Kupffer cells, decreased perfusion flow without rapid augmentation of enzyme leakage from galactosamine-treated liver. These results indicate that zymosan potentiates acute liver damage after galactosamine injection and suggest that certain types of nonparenchymal cells other than Kupffer cells are mainly involved in the action of zymosan.

Selection of severely head injured patients for mild hypothermia therapy

OBJECT

The authors have analyzed the efficacy of inducing mild hypothermia (34 degrees C) in 62 severely head injured patients to control fulminant intracranial hypertension.

METHODS

All 62 patients fulfilled the following criteria: 1)persistent intracranial pressure (ICP) greater than 20 mm Hg despite fluid restriction, hyperventilation, and high-dose barbiturate therapy; 2) an ICP lower than the mean arterial pressure; and 3) a Glasgow Coma Scale (GCS) score of 8 or less on admission. The patients were divided into three groups based on computerized tomography findings: extracerebral hematoma (34 patients with subdural and/or epidural hematoma), focal cerebral lesion (20 patients with localized brain contusion and/or intracerebral hematoma), and diffuse swelling (eight patients with no focal mass lesion). Mild hypothermia prevented ICP elevation in 35 (56.5%) of the 62 patients whose ICP was greater than 20 mm Hg despite conventional therapies. Among those 35 patients whose ICP was controlled by mild hypothermia, 12 (34.3%) achieved functional recovery (good outcome or moderate disability). However, functional recovery was observed in only five (10.9%) of the 46 patients whose ICP was greater than 40 mm Hg after conventional therapies. Of 40 patients with an admission GCS score of 5 to 8, there were 11 (27.5%) who achieved functional recovery. On the contrary, mild hypothermia was not effective in 22 patients with an admission GCS score of 3 or 4. In the patients with focal cerebral lesions, ICP was controlled by mild hypothermia in 17 patients (85%) and patient outcome was intimately related to the extent of the damage. Among 18 patients with extracerebral hematoma who had a midline shift of 9 to 12 mm, raised ICP could be successfully controlled by mild hypothermia in 16 patients (88.9%) and three (16.7%) achieved functional recovery. However, ICP could not be controlled in patients with extracerebral hematoma who had a midline shift of 13 mm or more. In patients with diffuse swelling, ICP elevation could not be prevented at all by mild hypothermia.

CONCLUSIONS

The authors conclude that mild hypothermia is effective for preventing ICP elevation in patients without diffuse brain swelling in whom ICP remains higher than 20 mm Hg but less than 40 mm Hg after conventional therapies.

Endothelin 1 aggravates acute liver injury in perfused livers of rats after treatment with D-galactosamine

The effects of endothelin 1 (ET-1) on hemodynamics and acute liver damage were studied using perfused livers of rats treated with D-galactosamine. In control liver perfused in situ with constant pressure, infusion of ET-1 into the portal vein at a concentration of 0.1 nmol/L decreased the flow rate without a significant leakage of lactate dehydrogenase (LDH) or aspartate transaminase (AST) into the effluent. In contrast, in similarly perfused liver 24 hours after treatment with D-galactosamine (800 mg/kg intraperitoneally), ET-1 caused rapid and remarkable increases in the leakage of LDH and AST from the liver accompanied by the reduction of perfusion flow to the extent similar to that observed in control livers. In addition, ET-1 decreased oxygen uptake and bile secretion in galactosamine-treated livers. The potentiating effects of ET-1 on enzyme leakage were also observed under constant flow conditions. Moreover, infusion of the thromboxane A2 analogue at a concentration of 10 nmol/L decreased the flow rate markedly, yet the rapid increases in enzyme leakage were not observed. Infusion of ET-3 induced the responses of flow reduction and the potentiation of rapid enzyme leakage similar to those obtained with ET-1. Neither the endothelin A-receptor antagonist BQ485 nor the endothelin B-receptor antagonist BQ788 could inhibit the acute liver damage caused by ET-1; instead they exaggerated its effects. The combination of both antagonists together, however, almost completely suppressed the flow reduction and the potentiation of enzyme leakage caused by ET-1. These results indicate that ET-1 is capable of aggravating acute liver damage not merely through reduction of the flow rate but through direct action on liver cells. They also suggest that both the endothelin A and endothelin B receptors are involved in this action of ET-1.

Two regions of the Mn-stabilizing protein from Synechococcus elongatus that are involved in binding to photosystem II complexes

Limited proteolysis of the Mn-stabilizing protein (MSP) from the thermophilic cyanobacterium Synechococcus elongatus with chymotrypsin, trypsin or lysylendopeptidase that yielded four major polypeptides of 26 kDa, 22 kDa, 15 kDa and 11 kDa on denaturing gel electrophoresis resulted in total loss of the binding capacity of the protein to PSII complexes. Analyses of electrophoretic patterns and amino-terminal sequences of the proteolytic products revealed that the three proteases specifically cleaved the protein at a site between Phe156 and Gly163 or between Arg184 and Ser191. Site-directed mutagenesis was used to construct two mutant MSPs that had a nick between Phe156 and Leu157, a chymotrypsin-cleavage site, and Met before Leu157 or in place of Leu157. The two mutant proteins failed to bind to PSII complexes, although they largely retained ordered secondary structure and comigrated with the wild-type proteins in non-denaturing gel electrophoresis. The loss of the protein binding can be ascribed to introduction of a nick because a mutant protein that had Met in place of Leu157 but no nick was able to specifically bind to the functional site of PSII complexes and restore the oxygen-evolving activity as effectively as the wild-type protein. In contrast, a mutant MSP with Met inserted between Phe156 and Leu157 bound only weakly and non-specifically to PSII complexes and failed to reactivate oxygen evolution. Thus, the binding of the protein to the functional site of the PSII complex was highly sensitive to a small structural change that was caused by cleavage or insertion of a single amino acid residue between Phe156 and Leu157. The results suggest that the Phe156-Gly163 and Arg184-Ser191 sequences of the cyanobacterial MSP are regions for interaction with PSII complexes.

Profiles of circulating inflammatory- and anti-inflammatory cytokines in patients with hemolytic uremic syndrome due to E. coli O157 infection

The systemic inflammatory response to Escherichia coli O157 infection was studied from the profiles of circulating inflammatory and anti-inflammatory cytokines. Twelve patients transferred sequentially to our hospital for the intensive care with acute illness due to Escherichia coli O157 infection and the possible form of haemolytic uraemic syndrome were included in this study. Increased circulating concentrations of tumour necrosis factor, interleukin 6, interleukin 8, granulocyte colony-stimulating factor, and interleukin 10 were found in patients with various stages of this infection and haemolytic uraemic syndrome. Especially, the degree of the increase of circulating interleukin 10 in those who had a typical signs of haemolytic uraemic syndrome was higher than those of other inflammatory cytokines. Two groups of E. coli infection could be classified into one with a typical haemolytic uraemic syndrome and the other with atypically bacteremic state over haemolytic uraemic syndrome according to these cytokine levels.

Post-transcriptional control of the level of mRNA by hepatitis B virus X gene in the transient expression system using human hepatic cells

BACKGROUND

Hepatitis B virus (HBV) infection is closely related to the development of not only acute or chronic hepatitis, but also hepatocellular carcinoma. Among the HBV genes, the X gene has been implicated in the carcinogenicity of this virus as a major causative factor by its ability to activate viral and cellular genes in trans via protein-protein interaction with cellular factors without binding to DNA.

RESULTS

To explore the possibility of other functions of the X gene, we examined the effect of X protein on the transient expression system of simian virus 40 (SV40) large T-antigen or chloramphenicol acetyltransferase (CAT) mRNA using SV40 promoter or EF-1alpha (human elongation factor 1alpha) promoter, by co-transfecting an X gene expression plasmid to human hepatic cell lines, HepG2 and Huh7. In contrast to the SV40 promoter-mediated expression, the level of both T-antigen and CAT mRNAs expressed from the EF-1alpha promoter was strikingly decreased by X protein in both hepatic cells. The nuclear run-on assay and the mRNA decay experiment using actinomycin D, indicated that the effect of X protein on the lowering of the level of chimeric mRNA was due to the degradation of mRNA, but not repression of transcriptional initiation. Moreover, this effect was dependent on the 22 bp sequence in the 5' untranslated region of mRNA derived from the EF-1alpha promoter.

CONCLUSION

The present data suggest a new function of the X gene to post-transcriptionally control the stability of mRNA through the 5' untranslated region derived from the EF-1alpha promoter in human hepatic cells.

Recombinant human granulocyte colony-stimulating factor attenuates inflammatory responses in septic patients with neutropenia

OBJECTIVE

The objective of this study was to determine the effects of recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration in septic patients with neutropenia.

METHODS

Twenty consecutive septic patients were administered rhG-CSF subcutaneously (2 microg x kg(-1) x d(-1)) for 5 days (group G). They were compared with 14 septic patients treated earlier without rhG-CSF (group N). All patients in both groups met the criteria of total leukocyte count (TLC) less than 5,000/mm3 and C-reactive protein (CRP) more than 10 mg/dL. Changes in TLC, absolute neutrophil count (ANC), CRP, respiratory index (RI), Acute Physiology and Chronic Health Evaluation (APACHE) II score, and Goris's Multiple Organ Failure (MOF) index were evaluated. In addition, nucleated cell count (NCC), differentiation in bone marrow aspiration, neutrophil phagocytic and bactericidal activity, serum concentrations of interleukin-6 (IL-6) and IL-8 as inflammatory markers, and plasma concentration of leukocyte elastase (LE) as an indicator of the tissue injury were evaluated in group G.

RESULTS

In group G, TLC, ANC, NCC, and neutrophil functions increased significantly, whereas CRP, IL-6, and IL-8 decreased reciprocally. There was no deterioration of LE and RI. Consequently, the APACHE II score and MOF index improved. In group N, however, CRP showed no change concomitant with the APACHE II score and MOF index.

CONCLUSION

Administration of rhG-CSF attenuates inflammatory responses without inducing tissue injury in septic patients with neutropenia.

Overview of evacuation and transport of patients following the 1995 Hanshin-Awaji earthquake

We investigated how patients were evacuated and transported from affected hospitals in the disaster area to backup hospitals following the 1995 catastrophic Hanshin-Awaji earthquake. A retrospective review was conducted of medical records of 6107 patients hospitalized during the first 15 days after the earthquake, collected from 48 affected hospitals in the disaster area and 47 backup hospitals in the surrounding area. Of the 6107 patients, a total of 2290 (38%) were transferred to backup hospitals, consisting of 187 patients (50%) with crush syndrome, 702 (26%) with other traumas, and 1401 (41%) with illness. Of those 2290 patients, 1741 (76%) were transferred from affected hospitals to backup hospitals, while 549 patients (24%) were evacuated directly to backup hospitals. The peak in transport came during the first 4 days. The family car was the most frequently used means of transport; ambulance was used in only 26% of cases, and helicopters were used minimally. There was no notable difference in the percentage of intensive care patients and nonintensive care patients transferred to backup hospitals. The mortality rate for patients with trauma and crush syndrome was significantly higher in the affected hospitals. These results suggest that the existing emergency medical service system was not adequate for this urban earthquake. From our vantage point, we are keenly aware of the need for improved communications between hospitals, a well equipped patient transport system, and a well coordinated disaster response mechanism.

A poison information service via an automated facsimile (fax) system: an adjunct to the operator-based service

BACKGROUND

Poison centers are faced with the escalating costs of specialist staffing and increased investments in hardware and databases despite deficit funding. We developed an automated fax information system to access poison information from any fax machine without special training or equipment.

METHODS

We provided a 3-month trial service of the fax system in conjunction with the regular operator-based service and analyzed the fax access log, followed by a questionnaire to the 2204 affiliate members regarding the use of the fax.

RESULTS

A total 657 accesses to the fax system were made, of which 105 (16%) were unsuccessful; 342 (52%) were made to retrieve the user's manual, 85 (13%) to retrieve the index pages, and 230 (35%) to retrieve documentation on specific substances. The most frequently accessed items concerned disc battery ingestion (13.5%), salicylates (10.3%), mamushi viper (7.1%), acetaminophen (5.8%), and sodium hypochlorite (3.8%). The questionnaires were returned by 666 (30.2%) members; 93 (14%) had actually used the fax system with the average frequency of 1.8 times/user, 63% (59/93) of the respondents considered the service satisfactory, and 33% (31/93) said it was somewhat unsatisfactory.

CONCLUSIONS

The automated fax information system was accepted and handled by users with only minor difficulty. A facsimile information service may have a valuable role in providing poisoning information and has potential benefits in cases of environmental disasters.

[Hypouricemia in patients with meningitis]

Serum urate and sodium concentrations were measured in 23 patients with acute viral and bacterial meningitis. Serum urate level was 3.0 +/- 0.2 mg/dl (mean +/- S.D.) (3.6 +/- 1.2 mg/dl in male and 2.5 +/- 0.9 mg /dl in female) on admission, but gradually elevated with improvements of meningitis. It turned to 4.8 +/- 0.2 mg/dl after recovery, and the value on admission was significantly lower than that after recovery (p < 0.0001). Serum sodium level was 137.6 +/- 2.9 mEq/l on admission and 139.7 +/- 2.7 mEq/l after recovery; also lower in the former (p < 0.01). These results show that patients develop transient hypouricemia, which may be explained by SIADH (syndrome of inappropriate secretion of ADH), although SIADH is subclinical in most cases of meningitis.

Effects of noradrenaline on the cell-surface glucose transporters in cultured brown adipocytes: novel mechanism for selective activation of GLUT1 glucose transporters

Glucose transport into rat brown adipocytes has been shown to be stimulated directly by the sympathetic neurotransmitter, noradrenaline, without a significant increase in the protein content of either GLUT1 or GLUT4 glucose transporter in the plasma membrane [Shimizu, Kielar, Minokoshi and Shimazu (1996) Biochem. J. 314, 485-490]. In the present study, we labelled the exofacial glucose-binding sites of GLUT1 and GLUT4 with a membrane-impermeant photoaffinity reagent, 2-N-[4-(1-azitrifluoroethyl)benzoyl]-[2-3H]1,3-bis- (D-mannos-4-yloxy)-2-propylamine (ATB-[3H]BMPA), to determine which isoform is responsible for the noradrenaline-induced increase in glucose transport into intact brown adipocytes in culture. Insulin stimulated the rate of hexose transport by increasing ATB-[3H]BMPA-labelled cell-surface GLUT4. In contrast, the noradrenaline-induced increase in glucose transport was not accompanied by an increased ATB-[3H]BMPA labelling of GLUT4, nor with an increased amount of GLUT4 in the plasma membrane fraction as assessed by Western blotting, indicating that noradrenaline does not promote the translocation of GLUT4. However, noradrenaline induced an increase in photoaffinity labelling of cell-surface GLUT1 without an apparent increase in the immunoreactive GLUT1 protein in the plasma membrane. This is suggestive of an increased affinity of GLUT1 for the ligand. In fact, the Ki value of non-radioactive ATB-BMPA for 2-deoxy-D-glucose uptake was significantly decreased after treatment of the cells with noradrenaline. The increased photoaffinity labelling of GLUT1 and increased glucose transport caused by noradrenaline were inhibited by a cAMP antagonist, cAMP-S Rp-isomer. These results demonstrate that noradrenaline stimulates glucose transport in brown adipocytes by enhancing the functional activity of GLUT1 through a cAMP-dependent mechanism.

Noradrenaline and ATP decrease the secretion of triglyceride and apoprotein B from perfused rat liver

To explore the role of hepatic sympathetic nerves on the secretion of very low density lipoprotein (VLDL), the effects of sympathetic neurotransmitters, noradrenaline and ATP, on the secretion of triglyceride and apoprotein B (ApoB) from the liver were studied using rat liver perfused in situ with recirculation. During liver perfusion with physiological medium, the amount of triglyceride in the perfusate was increased linearly for up to 120 min. The addition of noradrenaline to the perfusion medium at a final concentration of 1 muM increased the portal pressure and suppressed the secretion of triglyceride to about 60% of control without an increase in free fatty acid production. The administration of ATP increased the portal pressure with kinetics different from those induced by noradrenaline, but suppressed the triglyceride secretion to an extent similar to that induced by noradrenaline. The suppressive effect of noradrenaline on triglyceride secretion was mimicked by an alpha-adrenoceptor agonist, phenylephrine, and was retained after the haemodynamic changes were prevented by sodium nitroprusside. The secretion of ApoB from the perfused liver was also inhibited by noradrenaline or ATP to about 70% of control. However, hepatic levels of mRNA for ApoB were not significantly altered by noradrenaline and ATP. Since ApoB is the major apoprotein in VLDL, these results suggest that the sympathetic neurotransmitters noradrenaline and ATP suppress the secretion of ApoB-containing lipoprotein including VLDL from the liver, probably acting on post-transcriptional processes.

Reversible MR findings of hemolytic uremic syndrome with mild encephalopathy

We report the reversible MR findings in a 7-year-old girl with hemolytic uremic syndrome and mild encephalopathy. The splenium of the corpus callosum showed isointense to low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, representing local edema. These findings returned to near normal on MR images obtained 1 week later. The patient recovered without CNS impairment.

[Clinical and pathophysiologic problems associated with smoke inhalation injury]

Smoke inhalation injury is one of the primary determinants of survival following major burn injury. The primary site of injury in smoke inhalation appears to be the small airway rather than the alveoli, and thus small airway occlusion caused by edema and pseudomembrane formation are the primary mechanisms of progressive hypoxia. Ventilation-perfusion (VA/Q) alterations after smoke inhalation are characterized by increased blood flow to low VA/Q compartments, although an increase in true shunt (VA/Q = 0) was not a consistent finding. This differs considerably from most adult respiratory distress syndrome (ARDS) patients or oleic acid-induced lung edema models, in which an increase in true shunt is the major mechanism of hypoxia. Such differences lead to different responses to nitric oxide (NO) inhalation therapy, and NO does not improve oxygenation and outcome in patients with smoke inhalation injury. In the treatment of inhalation injury, meticulous removal of pseudomembrane by fiberoptic bronchoscopy is essential, the use of high concentrations of oxygen should be avoided since it can cause absorption atelectasis. High-frequency percussive ventilation is a suitable treatment for inhalation injury, as it improves oxygenation and facilitates removal of pseudomembrane.

Paradoxical positive nitrogen balance in burn patients receiving high-dose administration of insulin for nutritional care

BACKGROUND

Nitrogen balance in patients who need high-dose administration of insulin has not been evaluated clinically. The purpose of this study was to compare the difference in nitrogen balance between burn patients who received high-dose administration of insulin and those who did not.

METHODS

This study was performed in 19 severely burned adults with no liver or kidney failure. Patients were divided into two groups on the basis of the mean ratio of administered insulin and calorie intake (I/C) for the initial 4 weeks, a high I/C group (n = 9) and a low I/C group (n = 10). There were no significant differences between the two groups regarding age, percentage of area burned, and body weight. Nitrogen balance, blood urea nitrogen, and urine urea nitrogen were measured in all patients. Plasma concentrations of glucose, insulin, glucagon, cortisol, and urinary excretion of 3-methyl-histidine were measured in 12 patients (six in each group).

RESULTS

Until day 10 both groups exhibited similar changes in plasma concentrations of glucose, insulin, glucagon, and cortisol. Subsequently, plasma concentrations of insulin and glucagon began to decrease in the low I/C group, whereas a high level was sustained in the high I/C group (p < 0.05). Plasma glucose and cortisol measurements showed no significant differences between the two groups. Blood urea nitrogen levels and urinary excretion of 3-methyl-histidine were not different between the two groups. Urine urea nitrogen excretion in the high I/C group, however, was significantly lower than that in the low I/C group from day 8 (p < 0.05). Thus the high I/C group achieved positive nitrogen balance more quickly than the low I/C group. Paradoxically, however, the high I/C group was at higher risk of septic complications and exhibited higher mortality than the low I/C group (p < 0.05).

CONCLUSIONS

These results indicate that an improvement in nitrogen balance, which is accepted as a good thing in the management of critically ill patients, is not necessarily good in the high I/C group and that residual nitrogen was retained within the body in the high I/C group.

Analysis of 2,702 traumatized patients in the 1995 Hanshin-Awaji earthquake

BACKGROUND

This study was undertaken to define the factors that affected the final outcome of trauma patients in the Hanshin-Awaji earthquake.

METHODS

Medical records of patients admitted to 95 hospitals within or surrounding the affected area during the first 15 days after the quake were reviewed.

RESULTS

There were 2,702 traumatized patients. One-third of the patients were transported to hospitals in the surrounding area and had a mortality rate of 3%. The remainder, who were treated in the affected hospitals, showed a significantly higher mortality rate (8%; p < 0.05). Intensive care was provided for 513 patients, most of whom suffered from crush syndrome or from injuries to vital organs; these patients had a high mortality rate. Patients with other types of injuries had a lower mortality rate.

CONCLUSION

Crush syndrome and injuries to vital organs were potentially life-threatening. We believe that early transportation of such patients to undamaged hospitals with the ability to provide intensive care would have improved the survival rate.

The beta3-adrenergic agonist BRL37344 increases glucose transport into L6 myocytes through a mechanism different from that of insulin

In the present study, we examined the effects of BRL37344, a selective beta3-adrenergic agonist, on glucose transport into L6 myocytes and the results were compared with the effects of insulin. Insulin increased 2-deoxyglucose (2-DG) uptake in a dose-dependent manner, with maximal stimulation at 10(-7)M. BRL37344 ranging from 10(-7) to 10(-5)M also enhanced 2-DG uptake in the absence of insulin. The effects of insulin and BRL37344 were completely additive, suggesting that these two agents enhance glucose uptake by L6 myocytes through different mechanisms. In fact, BRL37344 apparently did not increase tyrosine phosphorylation of cellular proteins in L6 myocytes, whereas insulin stimulated tyrosine phosphorylation of 180-190 and 95 kDa proteins. Furthermore, BRL37344-induced increase in glucose transport was not blocked by wortmannin, an inhibitor of phosphatidylinositol 3-kinase, whereas the insulin-induced effect was completely abolished. When L6 myocytes were incubated with insulin, the content of GLUT4 in the plasma membrane was increased. However, BRL37344 did not affect the GLUT4 content in the plasma membrane. BRL37344 did not increase the Vmax value for glucose uptake but decreased the Km value, although insulin increased the Vmax value. These results suggest that BRL37344 enhances glucose transport into L6 myocytes through a signaling pathway different from that of insulin and that the mechanism does not involve the translocation of GLUT4, but may be due to an increase in the intrinsic activity of GLUT present in the plasma membrane.

Transcriptional activation of the human c-myc gene by simian virus 40 large T antigen without binding to p53 and RB proteins in the transient expression system

Transcriptional activation of the human c-myc gene by SV40 large T antigen was examined using HepG2 cells by co-transfecting a T antigen expression plasmid with a myc-CAT construct containing the 2.3-kb upstream region from the P1 promoter and the P2 promoter region fused to the CAT gene. T antigen increased the basal activity of the P2 promoter region containing the E2F binding site, but both the P2 promoter region and the upstream region from the P1 promoter were important for overall activation by T antigen. CAT assay using mutated T antigen lacking p53 or the RB binding site indicated that p53 or RB was not mainly involved in transcriptional activation of the c-myc gene. It appears that activation of the c-myc gene by T antigen is probably dependent upon E2F and a cellular factor through a mechanism which is independent of binding of T antigen to p53 and RB.

Fluid resuscitation and systemic complications in crush syndrome: 14 Hanshin-Awaji earthquake patients

BACKGROUND

Crush syndrome is a form of traumatic rhabdomyolysis characterized by systemic involvement, in which acute renal failure is potentially life-threatening.

METHODS

Clinical and laboratory data of 14 crush-syndrome patients transferred to a tertiary emergency department after the Hanshin-Awaji earthquake were analyzed. The patients were buried under collapsed houses for the average of 6.7 +/- 5.7 (SD) hours (range, 1 to 24 hours). They were referred to us 6 to 250 hours after the earthquake.

RESULTS

Of those who arrived at our institution within 40 hours, 25% (two of eight) developed renal failure, whereas all six patients who arrived after 40 hours developed renal failure. Peak serum creatine kinase ranged from 6,677 to 134,200 U/L (51,674 +/- 41,776). Renal failure was highly associated with massive muscle damage (serum creatine kinase above 25,000 U/L) and insufficient initial fluid resuscitation (below 10,000 mL/2 days).

CONCLUSIONS

Prompt and adequate, if not massive, fluid resuscitation is the key to preventing renal failure after such injury.

Analysis of 372 patients with Crush syndrome caused by the Hanshin-Awaji earthquake

OBJECTIVE

To clarify clinical features and determine the severity of injuries in patients with crush syndrome in Hanshin-Awaji earthquake.

METHODS

We retrospectively reviewed medical records of 6,107 patients hospitalized in 95 hospitals, and identified 372 patients with crush syndrome.

RESULTS

The major sites of crush injury were in the lower extremities (74%), followed by the upper extremities (10%), and the trunk (9%). Pelvic fractures, limb fractures, and abdominal injuries were the most frequently associated injury. Patients with trunk compression and/or with abdominal injury had a higher mortality rate. A total of 50 patients (13.4%) died. The causes of death within 5 days after the earthquake were hypovolemia and hyperkalemia. Peak serum creatine kinase concentration increased with the number of crushed extremities. Mortality and the risk of acute renal failure were higher in patients with creatine kinase concentration more than 75,000 micro/L.

CONCLUSIONS

Peak serum concentration of creatine kinase as well as the number of injured extremities serve to estimate the severity of crush syndrome.

Studies on the response of nitroglycerin oral spray compared with sublingual tablets for angina pectoris patients with dry mouth. A multicenter trial

Nitroglycerin (glyceryl trinitrate, CAS 55-63-0, NTG) administered with an oral spray may be more effective in relieving anginal pain than sublingual tablets especially when the patient's mouth is dry. In this study, the effect of a NTG oral spray (Myocor Spray) on exercise-induced angina was compared with that of a sublingual tablet in relation to the oral dryness. In 17 patients with effort angina, graded bicycle exercise was performed twice at an interval of one week. Exercise was discontinued upon the onset of moderate anginal pain. Immediately after exercise, the oral dryness was evaluated by touching the tip of the tongue with a blotting paper for a moment. Then, 0.3 mg of NTG was administered by either a squirt of spray or a sublingual tablet in a randomized crossover fashion. Exercise results were reproducible between two exercise tests. According to the extent of the wet area of the blotting paper, the subjects were divided into two groups. In 7 patients of the wet group, the remission times of chest pain and ST segment depression were not significantly different by the formulation of NTG. In 10 patients of the dry group, however, both chest pain and ST depression more rapidly recovered with use of the oral spray (p < 0.05 and p < 0.05, respectively). These results strongly suggest that the NTG oral spray is superior to the sublingual tablet in relieving anginal attacks, when the oral wetness is decreased.

Activation of mitogen-activated protein kinase by norepinephrine in brown adipocytes from rats

We have investigated the adrenergic control of mitogen-activated protein kinase (MAPK) activity in brown adipocytes. Cold exposure in rats led to an activation of MAPK in brown adipose tissue, as determined by the gel mobility shift assay and in-gel kinase assay. In contrast, no activation was seen after surgical sympathetic denervation of the tissue. The neurotransmitter, norepinephrine (NE), directly activated MAPK of brown adipocytes in primary cultures in the absence of insulin and serum. NE-induced activation of MAPK was mimicked by beta-adrenergic agonists, including a beta 3-agonist, BRL37344. Activation of MAPK also was observed by an alpha-agonist, phenylephrine, the extent of which being much lower than that by beta-agonists. The effect of NE was attenuated by the beta-adrenergic antagonist, propranolol. Dibutyryl cAMP also mimicked the effect of NE. The phorbol ester, phorbol-12-myristate, 13-acetate(PMA), could induce activation of MAPK, but pretreatment of the cultured cells with PMA to down-regulate protein kinase C did not abolish the ability of NE in activating MAPK. Furthermore, a selective inhibitor of phosphatidylinositol-3 kinase, wortmannin, did not inhibit the effect of NE, whereas insulin-induced activation of MAPK was totally suppressed. These results demonstrate that NE activates MAPK directly in brown adipocytes and that the effect of NE is not mediated by PMA-sensitive protein kinase C or wortmannin-sensitive phosphatidylinositol-3 kinase but rather is likely to be dependent on beta-receptor-mediated increase in cAMP with a minor contribution of alpha-receptor-mediated signals.

Ventilation-perfusion alterations after smoke inhalation injury in an ovine model

To study the pathophysiological mechanism of progressive hypoxemia after smoke inhalation injury, alterations in ventilation-perfusion ratio (VA/Q) were studied in an ovine model by using the multiple inert gas elimination technique. Because ethane was detected in expired gas of some sheep, we replaced ethane with krypton, which was a unique application of the multiple inert gas elimination technique when one of the experimental gases is present in the inspirate. Severity-related changes were studied 24 h after injury in control and mild, moderate, and severe inhalation injury groups. Time-related changes were studied in controls and sheep with moderate injury at 6, 12, 24, and 72 h. Arterial PO2 decreased progressively with severity of injury as well as with time. In smoke-exposed animals, blood flow was recruited to low VA/Q compartment (0 < VA/Q < 0.1; 17.6 +/- 10.6% of cardiac output, 24 h, moderate injury) from normal VA/Q compartment (0.1 < VA/Q < 10). However, increases in true shunt (VA/Q = 0; 5.6 +/- 2.5%, 24 h, moderate injury) and dead space were not consistent findings. The VA/Q patterns suggest the primary change in smoke inhalation injury to be a disturbance of ventilation.

Prolonged decrease in hepatic connexin32 in chronic liver injury induced by carbon tetrachloride in rats

BACKGROUND/AIMS

Our previous study indicated that the amount of connexin32, the major gap-junctional protein of rat liver, is transiently reduced in acute liver injury after single administration of hepatotoxic chemicals. This study was designed to examine alteration in the expression of connexin32 in chronic liver injury, unassociated with hepatocyte proliferation.

METHODS

Rats were injected with carbon tetrachloride (CCI4, 0.5 ml/kg) twice a week for 12 weeks. After cessation of CCI4 injection, hepatic contents of connexin32 and its mRNA levels were measured by immunoblotting as well as immunohistochemical examination and by Northern-blot analysis.

RESULTS

The plasma alanine-aminotransferase activity was increased from 30 U/I to about 1000 U/l after 12 weeks of CCI4 injections, but recovered nearly to normal level in 7 days after cessation of the injection. Liver specimens 12 days after the last CCI4 injection appeared cirrhotic with a marked increase in fibrosis. Connexin32 contents in these livers decreased to about 37% of controls. The significant decrease in connexin32 content was sustained for at least 30 days and recovered to the control level by 60 days. The alteration of connexin32 content in chronically injured liver was confirmed immunohistochemically. The level of connexin32-mRNA, however, was not reduced, but rather increased by chronic injection of CCI4.

CONCLUSION

The results suggest that intercellular communication is disturbed in chronic liver injury, lasting even after recovery from the acute phase of injury. Since the mRNA levels of connexin32 were sustained, the prolonged decrease in connexin32 contents in these livers might be due to a post-transcriptional change that causes decrease in protein synthesis or a derangement of post-translational controls.

Changes in granulocyte colony-stimulating factor concentration in patients with trauma and sepsis

OBJECTIVE

To better understand the role of granulocyte colony-stimulating factor (G-CSF) after the inflammatory response.

DESIGN

Serum G-CSF concentrations were measured serially in 19 trauma and 15 sepsis patients. Changes in G-CSF concentration were compared with those in the neutrophil ratio, phagocytic and bactericidal activities, and other cytokines.

MEASUREMENTS AND MAIN RESULTS

G-CSF concentrations in trauma patients were elevated on day 1, but quickly decreased within 7 days. G-CSF reached its maximum 3 hours after injury, parallel with peaks of interleukin-6 (IL-6) and IL-8, but not of tumor necrosis factor-alpha (TNF-alpha). In sepsis patients, G-CSF as well as TNF-alpha, IL-6, and IL-8 concentrations were markedly elevated at diagnosis and remained high during the course of the illness. These levels decreased significantly in the 11 survivors. Up to 3 days after the trauma, nonsegmented neutrophil ratios were higher than those thereafter. Neutrophil phagocytic and bactericidal activities remained normal during the course of disease in both conditions.

CONCLUSIONS

These results suggest that G-CSF plays an important role in the maturation and maintenance of function of neutrophils during the inflammatory response to trauma and sepsis.

Noradrenaline increases glucose transport into brown adipocytes in culture by a mechanism different from that of insulin

Glucose uptake into brown adipose tissue has been shown to be enhanced directly by noradrenaline (norepinephrine) released from sympathetic nerves. In this study we characterized the glucose transport system in cultured brown adipocytes, which responds to noradrenaline as well as insulin, and analysed the mechanism underlying the noradrenaline-induced increase in glucose transport. Insulin increased 2-deoxyglucose (dGlc) uptake progressively at concentrations from 10(-11) to 10(-6) M, with maximal stimulation at 10(-7) M. Noradrenaline concentrations ranging from 10(-8) to 10(-6) M also enhanced dGlc uptake, even in the absence of insulin. The effects of noradrenaline and insulin on dGlc uptake were additive. The stimulatory effect of noradrenaline was mimicked by the beta3-adrenergic agonist, BRL37344, at concentrations two orders lower than noradrenaline. Dibutyryl cyclic AMP also mimicked the stimulatory effect of noradrenaline, and the antagonist of cyclic AMP, cyclic AMP-S Rp-isomer, blocked the enhancement of glucose uptake due to noradrenaline. Furthermore Western blot analysis with an anti-phosphotyrosine antibody revealed that, in contrast with insulin, noradrenaline apparently does not stimulate intracellular phosphorylation of tyrosine, suggesting that the noradrenaline-induced increase in dGlc uptake depends on elevation of the intracellular cyclic AMP level and not on the signal chain common to insulin. When cells were incubated with insulin, the content of the muscle/adipocyte type of glucose transporter (GLUT4) in the plasma membrane increased, with a corresponding decrease in the amount in the microsomal membrane. In contrast, noradrenaline did not affect the subcellular distribution of GLUT4 or that of the HepG2/erythrocyte type of glucose transporter. Although insulin increased Vmax. and decreased the Km value for glucose uptake, the effect of noradrenaline was restricted to a pronounced decrease in Km. These results suggest that the mechanism by which noradrenaline stimulates glucose transport into brown adipocytes is not due to translocation of GLUT but is probably due to an increase in the intrinsic activity of GLUT, which is mediated by a cyclic AMP-dependent pathway.