Heat shock protein B8 promotes proliferation and migration in lung adenocarcinoma A549 cells by maintaining mitochondrial function.

Heat shock protein B8 (HSPB8) impacts on tumor proliferation and migration of malignancy. However, the role of HSPB8 in lung adenocarcinoma (LUAC) remains unclear. The aim of this study, therefore, was to clarify whether HSPB8 could bring benefits to proliferation and migration of LUAC and its underlying mechanisms. The expression of HSPB8 was first evaluated by immunohistochemistry in 35 LUAC samples. Then, A549 lung adenocarcinoma cells were transfected with pcDNA-HSPB8 or si-HSPB8 to induce HSPB8 overexpression and silence. Cellular activity was evaluated with a Cell Counting Kit-8 (CCK-8) assay. Cell proliferation and migration were observed by EdU assay and scratch assay. Mitochondria-specific reactive oxygen species (mtROS) and membrane potential were measured using MitoSOX Red probe and JC-1 staining. Superoxide dismutase (SOD) activities and malondialdehyde (MDA) level were measured using commercial kits, respectively. HSPB8 protein, mitochondrial fusion protein MFN2 and mitochondrial fission protein p-Drp1/Drp1 were measured using western blot. Compared with the normal tissues, the expression of HSPB8 protein was higher in LUAC tissues and upregulation of HSPB8 protein was related to tumor size and tumor location. Furthermore, HSPB8 overexpression aggravated cell proliferation and migration of A549 cells. Mechanistically, HSPB8 suppressed mitochondrial impairment, leading to promoting the progress of A549 lung adenocarcinoma cells. These data demonstrate that HSPB8 plays an important role in progression of LUAC and may be a new target to treat LUAC.

Rapamycin inhibited the function of lung CSCs via SOX2.

The presence of cancer stem cells (CSCs) is the source of occurrence, aggravation, and recurrence of lung cancer. Accordingly, targeting killing the lung CSCs has been suggested to be an effective approach for lung cancer treatment. In this study, we showed that rapamycin inhibited the mammalian target of rapamycin (mTOR) signal transduction in A549 cells and improved the sensitivity to cisplatin (DDP). The mechanisms involve inhibition of the SOX2 expression, cell proliferation, epithelial-mesenchymal transition (EMT) phenotype, and sphere formation. Interestingly, knocked down SOX2 was a similar effect with rapamycin in A549 sphere. Furthermore, we showed that ectopic expression of Sox2 in A549 cells was sufficient to render them more resistant to rapamycin treatment in vitro. These data suggested that rapamycin inhibited the function of lung CSCs via SOX2. It will be of great interest to further explore the therapeutic strategies of lung cancer.

Peptide nucleic acids targeting mitochondria enhances sensitivity of lung cancer cells to chemotherapy.

Acquired resistance to chemotherapy is a major limitation for the successful treatment of lung cancer. Previously, we and others showed that formation of tumor spheres is associated with chemotherapy resistance in lung cancer cells, but the underlying mechanisms remained largely unknown. In the current study, we show that mitochondrial activity is significantly higher in A549 tumor spheres versus monolayer cells, establishing mitochondria as a putative target for antitumor therapy. To this end, we designed a peptide nucleic acids (PNAs) coupled with triphenylphosphonium (TPP) to target the displacement loop (D-loop) regulatory region of mitochondrial DNA (PNA-mito). Treatment with PNA-mito significantly disrupted mitochondrial gene expression, inhibited membrane potential and mitochondria fusion, resulting in proliferation inhibition and cell death. Consistently, in mouse xenograft models, PNA-mito could efficiently inhibit mitochondrial gene expression and block tumor growth. Treatment with a low dose of PNA-mito could significantly enhance the chemotoxicity of cisplatin (CDDP) in drug-resistant A549 tumor spheres. These results establish mitochondria-targeting PNAs as a novel strategy to enhance the accumulative therapeutic outcome of lung cancer.

Endobronchial hamartoma mimicking malignant lung tumor contralateral endobronchial metastasis: A case report.

RATIONALE: Endobronchial hamartoma, the most common benign lung tumor, is located in the bronchus, and it easily mimics lung cancer or bronchial metastasis. Endobronchial hamartoma can cause coughing, hemoptysis, and pulmonary infection; thus, it should be treated right away by surgery or fiberoptic bronchoscopy. PATIENT CONCERNS: We report a rare case of endobronchial hamartoma in which the clinical symptoms and imaging overlapped strongly with malignant lung tumor contralateral endobronchial metastasis. DIAGNOSES: Endobronchial hamartoma coexisting with a malignant lung tumor. INTERVENTIONS: Fiberoptic bronchoscopy was conducted, and the pathologic diagnosis was hamartoma. A second fiberoptic bronchoscopy was conducted, and fine-needle aspiration cytology of the enlarged lymph nodes indicated squamous cell carcinoma. OUTCOMES: The clinical symptoms were relieved, and the treatment options were docetaxel, cis-dichlorodiamineplatinum, and endostatin. LESSONS: Fiberoptic bronchoscopy needs to be guided by imaging and can be considered an effective method for the diagnosis of endobronchial hamartoma.

The association between MMP-12 82 A/G polymorphism and susceptibility to various malignant tumors: a meta-analysis.

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases responsible for degrading essentially all components of the extracellular matrix (ECM). Accumulating evidence suggests that MMPs might play a critical role in growth, invasion, and metastasis of malignant tumors. A single nucleotide polymorphism (SNP) in the promoter region of MMP-12, MMP-12 82 A/G (rs2276109), has been recognized to play a critical role in regulating the expression of MMP-12, however, its correlation with tumor susceptibility remains controversial. To address this issue, we performed meta-analysis to investigate the association MMP-12 82 A/G polymorphism and susceptibility of nine malignant tumors from 11 studies, including 6153 cancer patients and 6838 controls. Two reviewers independently screened studies for eligibility and extracted data for included studies. While overall no evident association between MMP-12 82 A/G and tumor susceptibility was observed, subgroup analysis revealed a specific role of G allele in increasing the susceptibility for epithelial ovarian carcinoma (EOC) using the allele model (fixed effects OR = 2.45, 95% CI = 1.46-4.10, P = 0.001) and the dominant model (fixed effects OR = 2.52, 95% CI = 1.49-4.24, P = 0.001). We thus suggest that G allele of MMP-12 82 A/G polymorphism is a genetic risk factor for EOC.

Enhanced expression of stem cell markers and drug resistance in sphere-forming non-small cell lung cancer cells.

There is growing evidence suggesting that cancer stem cells (CSCs) are playing critical roles in tumor progression, metastasis and drug resistance. However, the role of CSCs in non-small cell lung cancer (NSCLC) remains elusive. In this study, we enriched for stem-like cells from tumor spheres derived from NSCLC cell line A549 cultured in serum-free medium. Our results showed that sphere-derived cells expressed various stem cell markers such as CD44, CD133, Sox2 and Oct4. Compared with the corresponding cells in monolayer cultures, sphere-derived cells showed marked morphologic changes and increased expression of the stem cell markers CD133. Furthermore, we found that sphere-derived cells exhibited increased proliferation, cell-cycle progression as well as drug-resistant properties as compared to A549 adherent cells. Consistently, expression of several drug resistance proteins, including lung resistance-related protein (LRP), glutathion-S-transferase-π (GST-π) and multidrug resistance proteins-1 (MRP1) were all significantly enhanced in sphere-derived cells. These results indicate the enrichment of CSCs in sphere cultures and support their role in regulating drug resistance in NSCLC.

Impact of intraportal N(omega)-nitro-L-arginine infusion on hepatic glucose metabolism in total parenteral nutrition-adapted dogs: interaction with infection.

During chronic total parenteral nutrition (TPN), liver glucose uptake and lactate release are markedly elevated. However, in the presence of an infection, hepatic glucose uptake and lactate release are reduced. Glucose delivery (the product of liver blood flow and inflowing glucose concentration) is a major determinant of liver glucose uptake. Hepatic blood flow is increased during infection, and increased nitric oxide (NO) biosynthesis is thought to contribute to the increase. Our aim was to determine if the increase in liver blood flow served to limit the infection-induced decrease in hepatic glucose uptake and metabolism. Chronically catheterized conscious dogs received TPN for 5 days at a rate designed to match daily basal energy requirements. On the third day of TPN administration, a sterile (SHAM) or Escherichia coli (E. coli)-containing (INF) fibrin clot was implanted in the peritoneal cavity. Forty-two hours later, somatostatin was infused with intraportal replacement of insulin (10 +/- 2 v 23 +/- 2 microU/mL, SHAM v INF, respectively) and glucagon (22 +/- 4 v 90 +/- 8 pg/mL) to match concentrations observed in sham and infected animals. Tracer and arteriovenous difference techniques were used to assess hepatic glucose metabolism. Following a 120-minute basal sampling period, sham and infected animals received either intraportal saline or N(omega)-nitro-L-arginine (L-NNA; 37 microg x kg(-1) x min(-1)) infusion for 180 minutes. Isoglycemia (120 mg/dL) was maintained with a variable glucose infusion. In the infected group L-NNA infusion decreased hepatic arterial blood flow (23.3 +/- 0.7 to 8.6 +/- 0.5 mL x kg(-1) x min(-1)), but not portal vein blood flow. Neither portal vein nor hepatic artery blood flow were altered by L-NNA infusion in the sham group. Hepatic glucose uptake and lactate metabolism were not altered by L-NNA infusion in either group. In summary, during infection, an increase in NO biosynthesis contributes to the increase in hepatic arterial blood flow, while it exerts no effect on hepatic glucose metabolism.

Liver, but not muscle, has an entrainable metabolic memory.

Hyperglycemia in the hospitalized setting is common, especially in patients that receive nutritional support either continuously or intermittently. As the liver and muscle are the major sites of glucose disposal, we hypothesized their metabolic adaptations are sensitive to the pattern of nutrient delivery. Chronically catheterized, well-controlled depancreatized dogs were placed on one of three isocaloric diets: regular chow diet once daily (Chow) or a simple nutrient diet (ND) that was given either once daily (ND-4) or infused continuously (ND-C). Intraportal insulin was infused to maintain euglycemia. After 5 days net hepatic (NHGU) and muscle (MGU) glucose uptake and oxidation were assessed at euglycemia (120 mg/dl) and hyperglycemia (200 mg/dl) in the presence of basal insulin. While hyperglycemia increased both NHGU and MGU in Chow, NHGU was amplified in both groups receiving ND. The increase was associated with enhanced activation of glycogen synthase, glucose oxidation and suppression of pyruvate dehydrogenase kinase-4 (PDK-4). Accelerated glucose-dependent muscle glucose uptake was only evident with ND-C. This was associated with a decrease in PDK-4 expression and an increase in AMP-activated protein kinase (AMPK) phosphorylation. Interestingly, ND-C markedly increased hepatic FGF-21 expression. Thus, augmentation of carbohydrate disposal in the liver, as opposed to the muscle, is not dependent on the pattern of nutrient delivery.

Continuous low-dose fructose infusion does not reverse glucagon-mediated decrease in hepatic glucose utilization.

An adaptation to continuous total parenteral nutrition (TPN; 75% of nonprotein calories as glucose) is the liver becomes a major consumer of glucose with lactate release as a by-product. The liver is able to further increase liver glucose uptake when a small dose of fructose is acutely infused via the portal system. Glucagon, commonly elevated during inflammatory stress, is a potent inhibitor of glucose uptake by the liver during TPN. The aim was to determine if continuous fructose infusion could overcome the glucagon-mediated decrease in hepatic glucose uptake. Studies were performed in conscious, insulin-treated, chronically catheterized, pancreatectomized dogs that adapted to TPN for 33 hours. They were then assigned to 1 of 4 groups: TPN (C), TPN + fructose (4.4 µmol kg(-1) min(-1); F), TPN + glucagon (0.2 pmol kg(-1) min(-1); GGN), or TPN + fructose and glucagon (F + GGN) for an additional 63 hours (33-96 hours). Insulin, fructose, and glucagon were infused into the portal vein. During that period, all animals received a fixed insulin infusion of 0.4 mU·kg(-1)·min(-1) (33-96 hours); and the glucose infusion rates were adjusted to maintain euglycemia (6.6 mmol/L). Continuous fructose infusion was unable to further enhance net hepatic glucose uptake (in micromoles per kilogram per minute) (31.1 ± 2.8 vs 36.1 ± 5.0; C vs F), nor was it able to overcome glucagon-mediated decrease in net hepatic glucose uptake (10.0 ± 4.4 vs 12.2 ± 3.9; GGN vs F + GGN). In summary, continuous fructose infusion cannot augment liver glucose uptake during TPN; nor can it overcome the inhibitory effects of glucagon.

Glucagon-mediated impairments in hepatic and peripheral tissue nutrient disposal are not aggravated by increased lipid availability.

Glucose, fat, and glucagon availability are increased in diabetes. The normal response of the liver to chronic increases in glucose availability is to adapt to become a marked consumer of glucose. Yet this fails to occur in diabetes. The aim was to determine whether increased glucagon and lipid interact to impair the adaptation to increased glucose availability. Chronically catheterized well controlled depancreatized conscious dogs (n = 21) received 3 days of continuous parenteral nutrition (TPN) that was either high in glucose [C; 75% nonprotein calories (NPC)] or in lipid (HL; 75% NPC) in the presence or absence of a low dose (one-third basal) chronic intraportal infusion of glucagon (GN; 0.25 ng.kg(-1).min(-1)). During the 3 days of TPN, all groups received the same insulin algorithm; the total amount of glucose infused (GIR) was varied to maintain isoglycemia ( approximately 120 mg/dl). On day 3 of TPN, hepatic metabolism was assessed. Glucose and insulin levels were similar in all groups. GIR was decreased in HL and C + GN ( approximately 30%) and was further decreased in HL + GN (55%). Net hepatic glucose uptake was decreased approximately 15% in C + GN, and HL and was decreased approximately 50% in HL + GN. Lipid alone or combined with glucagon decreased glucose uptake by peripheral tissues. Despite impairing whole body glucose utilization, HL did not limit whole body energy disposal. In contrast, glucagon suppressed whole body energy disposal irrespective of the diet composition. In summary, failure to appropriately suppress glucagon secretion adds to the dietary fat-induced impairment in both hepatic and peripheral glucose disposal. In addition, unlike increasing the percentage of calories as fat, inappropriate glucagon secretion in the absence of compensatory hyperinsulinemia limits whole body nutrient disposition.

Glucagon chronically impairs hepatic and muscle glucose disposal.

Defects in insulin secretion and/or action contribute to the hyperglycemia of stressed and diabetic patients, and we hypothesize that failure to suppress glucagon also plays a role. We examined the chronic impact of glucagon on glucose uptake in chronically catheterized conscious depancreatized dogs placed on 5 days of nutritional support (NS). For 3 days of NS, a variable intraportal infusion of insulin was given to maintain isoglycemia (approximately 120 mg/dl). On day 3 of NS, animals received a constant low infusion of insulin (0.4 mU.kg-1.min-1) and either no glucagon (CONT), basal glucagon (0.7 ng.kg-1.min-1; BasG), or elevated glucagon (2.4 ng.kg-1.min-1; HiG) for the remaining 2 days. Glucose in NS was varied to maintain isoglycemia. An additional group (HiG+I) received elevated insulin (1 mU.kg-1.min-1) to maintain glucose requirements in the presence of elevated glucagon. On day 5 of NS, hepatic substrate balance was assessed. Insulin and glucagon levels were 10+/-2, 9+/-1, 7+/-1, and 24+/-4 microU/ml, and 24+/-5, 39+/-3, 80+/-11, and 79+/-5 pg/ml, CONT, BasG, HiG, and HiG+I, respectively. Glucagon infusion decreased the glucose requirements (9.3+/-0.1, 4.6+/-1.2, 0.9+/-0.4, and 11.3+/-1.0 mg.kg-1.min-1). Glucose uptake by both hepatic (5.1+/-0.4, 1.7+/-0.9, -1.0+/-0.4, and 1.2+/-0.4 mg.kg-1.min-1) and nonhepatic (4.2+/-0.3, 2.9+/-0.7, 1.9+/-0.3, and 10.2+/-1.0 mg.kg-1.min-1) tissues decreased. Additional insulin augmented nonhepatic glucose uptake and only partially improved hepatic glucose uptake. Thus, glucagon impaired glucose uptake by hepatic and nonhepatic tissues. Compensatory hyperinsulinemia restored nonhepatic glucose uptake and partially corrected hepatic metabolism. Thus, persistent inappropriate secretion of glucagon likely contributes to the insulin resistance and glucose intolerance observed in obese and diabetic individuals.

Route-dependent effect of nutritional support on liver glucose uptake.

The liver is a major site of glucose disposal during chronic (5 day) total parenteral (TPN) and enteral (TEN) nutrition. Net hepatic glucose uptake (NHGU) is dependent on the route of delivery when only glucose is delivered acutely; however, the hepatic response to chronic TPN and TEN is very similar. We aimed to determine whether the route of nutrient delivery altered the acute (first 8 h) response of the liver and whether chronic enteral delivery of glucose alone could augment the adaptive response to TPN. Chronically catheterized conscious dogs received either TPN or TEN containing glucose, Intralipid, and Travasol for either 8 h or 5 days. Another group received TPN for 5 days, but approximately 50% of the glucose in the nutrition was given via the enteral route (TPN+EG). Hepatic metabolism was assessed with tracer and arteriovenous difference techniques. In the presence of similar arterial plasma glucose levels (approximately 6 mM), NHGU and net hepatic lactate release increased approximately twofold between 8 h and 5 days in TPN and TEN. NHGU (26 +/- 1 vs. 23 +/- 3 micromol.kg(-1).min(-1)) and net hepatic lactate release (44 +/- 1 vs. 34 +/- 6 micromol.kg(-1).min(-1)) in TPN+EG were similar to results for TPN, despite lower insulin levels (96 +/- 6 vs. 58 +/- 16 pM, TPN vs. TPN+EG). TEN does not acutely enhance NHGU or disposition above that seen with TPN. However, partial delivery of enteral glucose is effective in decreasing the insulin requirement during chronic TPN.

Time course of the hepatic adaptation to TPN: interaction with glycogen depletion.

In response to chronic (5 days) TPN, the liver becomes a major site of glucose disposal, removing approximately 45% (4.5 mg.kg(-1).min(-1)) of exogenous glucose. Moreover, approximately 70% of glucose is not stored but released as lactate. We aimed to determine in chronically catheterized conscious dogs the time course of adaptation to TPN and the glycogen depletion impact on early time course. After an 18-h (n = 5) fast, TPN was infused into the inferior vena cava for 8 (n = 5) or 24 h (n = 6). A third group, of 42-h-fasted animals (n = 6), was infused with TPN for 8 h. TPN was infused at a rate designed to match the dog's calculated basal energy and nitrogen requirements. NHGU (-2.3 +/- 0.1 to 2.2 +/- 0.7 to 3.9 +/- 0.6 vs. -1.7 +/- 0.3 to 1.1 +/- 0.5 to 2.9 +/- 0.4 mg.kg(-1).min(-1), basal to 4 to 8 h, 18 vs. 42 h) and net hepatic lactate release (0.7 +/- 0.3 to 0.6 +/- 0.1 to 1.4 +/- 0.2 vs. -0.6 +/- 0.1 to 0.1 +/- 0.1 to 0.8 +/- 0.1 mg.kg(-1).min(-1), basal to 4 to 8 h) increased progressively. Net hepatic glycogen repletion and tracer determined that glycogen syntheses were similar. After 24 h of TPN, NHGU (5.4 +/- 0.6 mg.kg(-1).min(-1)) and net hepatic lactate release (2.6 +/- 0.4 mg.kg(-1).min(-1)) increased further. In summary, 1) most hepatic adaptation to TPN occurs within 24 h after initiation of TPN, and 2) prior glycogen depletion does not augment hepatic adaptation rate.

Impact of chronic fructose infusion on hepatic metabolism during TPN administration.

During chronic total parenteral nutrition (TPN), net hepatic glucose uptake (NHGU) is markedly elevated. However, NHGU is reduced by the presence of an infection. We recently demonstrated that a small, acute (3-h) intraportal fructose infusion can correct the infection-induced impairment in NHGU. The aim of this study was to determine whether the addition of fructose to the TPN persistently enhances NHGU in the presence of an infection. TPN was infused continuously into the inferior vena cava of chronically catheterized dogs for 5 days. On day 3, a bacterial clot was implanted in the peritoneal cavity, and either saline (CON, n = 5) or fructose (+FRUC, 1.0 mg. kg(-1). min(-1), n = 6) infusion was included with the TPN. Forty-two hours after the infection was induced, hepatic glucose metabolism was assessed in conscious dogs with arteriovenous and tracer methods. Arterial plasma glucose concentration was lower with chronic fructose infusion (120 +/- 4 vs. 131 +/- 3 mg/dl, +FRUC vs. CON, P < 0.05); however, NHGU was not enhanced (2.2 +/- 0.5 vs. 2.8 +/- 0.4 mg. kg(-1). min(-1)). Acute removal of the fructose infusion dramatically decreased NHGU (2.2 +/- 0.5 to -0.2 +/- 0.5 mg. kg(-1). min(-1)), and net hepatic lactate release also fell (1.6 +/- 0.3 to 0.5 +/- 0.3 mg. kg(-1). min(-1)). This led to an increase in the arterial plasma glucose (Delta13 +/- 3 mg/dl, P < 0.05) and insulin (Delta5 +/- 2 micro U/ml) concentrations and to a decrease in glucagon (Delta-11 +/- 3 pg/ml) concentration. In conclusion, the addition of chronic fructose infusion to TPN during infection does not lead to a persistent augmentation of NHGU.

Infection impairs insulin-dependent hepatic glucose uptake during total parenteral nutrition.

Total parenteral nutrition (TPN) markedly augments net hepatic glucose uptake (NHGU) and hepatic glycolysis in the presence of mild hyperglycemia and hyperinsulinemia. This increase is impaired by an infection. We determined whether the adaptation to TPN alters the responsiveness of the liver to insulin and whether infection impairs that response. Chronically catheterized dogs received TPN for 5 days. On day 3 of TPN, either a nonlethal hypermetabolic infection was induced (INF, n = 5) or a sham surgery was performed (SHAM, n = 5). Forty-two hours after clot implantation, somatostatin and glucagon (34 +/- 3 vs. 84 +/- 11 pg/ml in artery, SHAM vs. INF) were infused, and a three-step (120 min each) isoglycemic (approximately 120 mg/dl) hyperinsulinemic (approximately 12, 25, and 50 microU/ml) clamp was performed to simulate levels seen in normal, infected, and exogenous insulin treatment states. In SHAM, NHGU (3.5 +/- 0.2 to 4.2 +/- 0.4 to 4.6 +/- 0.5 mg x kg(-1) x min(-1)) modestly increased. In INF, NHGU was consistently lower at each insulin step (1.1 +/- 0.5 to 2.6 +/- 0.5 to 2.8 +/- 0.7 mg x kg(-1) x min(-1)). Although NHGU increased from the first to the second step in INF, it did not increase further with the highest dose of insulin. Despite increases in NHGU, net hepatic lactate release did not increase in SHAM and fell in INF. In summary, in the TPN-adapted state, liver glucose uptake is unresponsive to increases in insulin above the basal level. Although the infection-induced increase in insulin sustains NHGU, further increments in insulin enhance neither NHGU nor glycolysis.

Impact of infection on glucose-dependent liver glucose uptake during TPN: interaction with insulin.

Chronic total parenteral nutrition (TPN) markedly augments net hepatic glucose uptake (NHGU). This adaptive increase is impaired by an infection despite accompanying hyperinsulinemia. In the nonadapted state, NHGU is dependent on the prevailing glucose levels. Our aims were to determine whether the adaptation to TPN alters the glucose dependence of NHGU, whether infection impairs this dependence, and whether insulin modulates the glucose dependence of NHGU during infection. Chronically catheterized dogs received TPN for 5 days. On day 3 of TPN, dogs received either a bacterial fibrin clot to induce a nonlethal infection (INF, n = 9) or a sterile fibrin clot (Sham, n = 6). Forty-two hours after clot implantation, somatostatin was infused. In Sham, insulin and glucagon were infused to match the level seen in Sham (9 +/- 1 microU/ml and 23 +/- 4 pg/ml, respectively). In infected animals, either insulin and glucagon were infused to match the levels seen in infection (25 +/- 2 microU/ml and 101 +/- 15 pg/ml; INF-HI; n = 5) or insulin was replaced to match the lower levels seen in Sham (13 +/- 2 microU/ml), whereas glucagon was kept elevated (97 +/- 9 pg/ml; INF-LO; n = 4). Then a four-step (90 min each) hyperglycemic (120, 150, 200, or 250 mg/dl) clamp was performed. NHGU increased at each glucose step in Sham (from 3.6 +/- 0.6 to 5.4 +/- 0.7 to 8.9 +/- 0.9 to 12.1 +/- 1.1 mg.kg(-1).min(-1)); the slope of the relationship between glucose levels and NHGU (i.e., glucose dependence) was higher than that seen in nonadapted animals. Infection impaired glucose-dependent NHGU in both INF-HI (1.3 +/- 0.4 to 2.9 +/- 0.5 to 5.5 +/- 1.0 to 7.7 +/- 1.6 mg.kg(-1).min(-1)) and INF-LO (0.5 +/- 0.7 to 2.2 +/- 0.6 to 4.2 +/- 1.0 to 5.8 +/- 0.8 mg.kg(-1).min(-1)). In summary, TPN augments glucose-dependent NHGU, the presence of infection decreases glucose-dependent NHGU, and the accompanying hyperinsulinemia associated with infection does not sustain the glucose dependence of NHGU.