Biomedical subjects

J J Spitzer

Publications and source records attributed to J J Spitzer.

At least 127 records · Page 7Linked to original sources

PubMed1987

Glucose kinetics and pyruvate dehydrogenase activity in septic rats treated with dichloroacetate.

Decreased pyruvate dehydrogenase (PDH) activity in skeletal muscle has been observed during sepsis and may contribute to the altered glucose kinetics seen in this condition. The purpose of the present study was to determine if dichloroacetate (DCA), a known stimulator of PDH activity, could reverse the sepsis-induced increase in glucose metabolism. Hypermetabolic sepsis was produced in chronically catheterized rats by repeated subcutaneous injections of live Escherichia coli. Whole body glucose kinetics, assessed by a constant iv infusion of [6-3H and U-14C]-glucose, were determined in fasted septic and nonseptic rats before and for 4 hr after an injection of DCA (30 mg/100 g BW, iv). Sepsis produced hyperthermia (+1.6 degrees C) and increased the rates of glucose appearance (Ra; 95%), recycling (318%), metabolic clearance (MCR; 114%), and elevated plasma lactate levels (295%) compared to nonseptic controls. After injection of DCA into septic rats, glucose levels gradually fell, and the sepsis-induced hyperlactacidemia was completely reversed. Treatment of septic rats with DCA reversed the elevated glucose Ra; recycling, although reduced, was still elevated by 50% compared to control animals. DCA did not alter the hyperglucagonemia seen in septic animals, but it did reduce the plasma insulin levels by 60%. Hepatic and muscle PDH activities were not different in saline-treated septic and nonseptic animals. DCA elevated PDH activity in muscle from septic rats, but the increase was smaller than that seen in control animals. This may explain the smaller decline in glucose recycling and plasma lactate in septic animals. These results are consistent with DCA reducing the elevated glucose Ra in sepsis by partial activation of PDH, which reduces the elevated precursor (lactate) supply for gluconeogenesis. However, alterations in PDH activity did not appear to contribute to the underlying increase in glucose Ra and recycling observed in sepsis.

Acetates↗

PubMed1987

Attenuation of endotoxin-induced increase in glucose metabolism by platelet-activating factor antagonist.

Platelet-activating factor (PAF) has recently been proposed as a putative mediator of various pathophysiologic events during endotoxemia. The aim of the present study was to determine the relative importance of PAF in producing the alterations in carbohydrate metabolism following endotoxin. Chronically catheterized conscious rats were treated with SRI 63-441, a specific PAF receptor antagonist, or saline prior to Escherichia coli endotoxin (100 micrograms/100 g body weight, LD10) administration. Hemodynamic and whole-body glucose kinetic changes, the latter assessed by a constant intravenous infusion of [6-3H] glucose, were determined throughout the 4-hr experimental protocol. Endotoxin induced a transient 30-35% reduction in mean arterial blood pressure (MABP) in animals treated with saline. The PAF-antagonist attenuated this hypotensive effect, and MABP was only reduced by 14-18%. Endotoxin increased plasma glucose and lactate levels, as well as the rate of glucose appearance (Ra) in saline-treated rats. The PAF antagonist reduced the hyperglycemia by 60-75% and tended to prevent the hyperlactacidemia. The endotoxin-induced elevation in glucose Ra was also attenuated by 55%. A similar degree of hyperglucagonemia was observed following endotoxin in both groups, and plasma insulin concentrations were not different. However, plasma catecholamine levels were significantly lower (30-70%) in endotoxemic rats treated with the PAF antagonist. These results suggest that the enhanced production of PAF following endotoxin may be responsible, at least in part, for the early hemodynamic changes. The role of PAF as a mediator of endotoxin-induced glucose dyshomeostasis, however, may be secondary to its hemodynamic effects.

Animals↗

PubMed1987

Myocardial dysfunction in sepsis.

A synthesis of the postulated sequence of events for development of the inappropriate response of the myocardium to a demand for increased cardiac index is schematically represented in Fig. 10. In sepsis, bacteremia and/or the release of endotoxin activate the macrophages which release a spectrum of mediators. Some of these mediators (and possibly also endotoxin itself) have a negative influence on myocardial contractile function either directly and/or through altering cellular calcium flux. This results in impaired myocardial function manifested initially by decreased stroke volume. Subsequently, stroke volume will be either partially or completely restored to normal through the action of circulating catecholamines, the concentration of which is markedly elevated due to the presence of endotoxin and/or macrophage-produced mediators. Endotoxin and/or these mediators also act on the SA node increasing its sensitivity to beta-adrenergic stimulation. This will result in elevated heart rates. The latter, combined with the restored stroke volume, will yield an increased cardiac index which is the hallmark of the hyperdynamic phase of sepsis. In the cecal ligation and puncture model of sepsis, where cardiac index is maintained at the original level, the partially restored stroke volume and the elevated heart rate will combine to maintain cardiac index. Although this mechanism of increasing cardiac index through tachycardia is not energy efficient, the myocardium is able to cope with these changes and also to maintain its high energy phosphate concentrations, since the utilization of the three major myocardial substrates (fatty acids, lactate and glucose) is not affected by sepsis. Although this putative sequence of events is consistent with the observed experimental findings, further work is needed to substantiate its applicability to the etiology of myocardial dysfunction in man during sepsis.

Animals↗

PubMed1986

Plasma glucose concentration determines direct versus indirect liver glycogen synthesis.

In the present study hepatic glycogenesis by the direct versus indirect pathway was determined as a function of the glucose infusion rate. Glycogen synthesis was examined in catheterized conscious rats that had been fasted 48 h before receiving a 3-h infusion (iv) of glucose. Glucose, containing tracer quantities of [U-14C]- and [6-3H]glucose, was infused at rates ranging from 0 to 230 mumol X min-1 X kg-1. Plasma concentrations of glucose, lactate, and insulin were positively correlated with the glucose infusion rate. Despite large changes in plasma glucose, lactate, and insulin concentrations, the rate of hepatic glycogen deposition (0.46 +/- 0.03 mumol X min-1 X g-1) did not vary significantly between glucose infusion rates of 20 and 230 mumol X min-1 X kg-1. However, the percent contribution of the direct pathway to glycogen repletion gradually increased from 13 +/- 2 to 74 +/- 4% in the lowest to the highest glucose infusion rates, with prevailing plasma glucose concentrations from 9.4 +/- 0.5 to 21.5 +/- 2.1 mM. Endogenous glucose production was depressed (by up to 40%), but not abolished by the glucose infusions. Only a small fraction (7-14%) of the infused glucose load was incorporated into liver glycogen via the direct pathway irrespective of the glucose infusion rate. Our data indicate that the relative contribution of the direct and indirect pathways of hepatic glycogen synthesis are dependent on the glucose load or plasma glucose concentration and emphasize the predominance of the indirect pathway of glycogenesis at plasma glucose concentrations normally observed after feeding.

Animals↗

PubMed1986

Glycogen synthase and phosphorylase activities during glycogen repletion in endotoxemic rats.

The activities of glycogen synthase and glycogen phosphorylase were quantitated in liver and skeletal muscle removed following glucose infusion in hemodynamically stable endotoxin-treated rats. Four hours after the IV injection of endotoxin or saline, rats were infused with 235 mumole/min/kg of glucose or saline for up to 4 additional hr. Saline-infused endotoxemic rats had lower basal glycogen content in muscle and liver, which was associated with an increased phosphorylase a activity in both tissues compared to controls. During the glucose infusion, the rate of glycogen repletion in muscle was similar in the two groups. Skeletal muscle phosphorylase a and glycogen synthase I & D activities were elevated above control values in endotoxemia, while glycogen synthase I activity remain unchanged. These changes in the activity of muscle phosphorylase and synthase are consistent with an increased flux of carbon into and out of glycogen and a normal rate of net glycogen synthesis during glucose infusion in endotoxin-treated rats. In contrast to muscle, hepatic glycogen synthesis by endotoxemic animals was reduced compared to glucose-infused controls. Hepatic glycogen repletion in control animals appeared to be mediated primarily by a glucose-induced suppression of phosphorylase a activity rather than an increased glycogen synthase activity. Glucose infusion failed to decrease phosphorylase a activity in endotoxin-treated rats, which may be causally related to the impaired ability of these animals to replete liver glycogen.

Animals↗

PubMed1986

Increased glucose metabolism by epitrochlearis muscle removed from endotoxin-treated rats.

In this study glucose metabolism was assessed in epitrochlearis muscle taken from control and endotoxin-treated rats. Endotoxin (1 mg/100 g) or saline was administered i.v. to rats and the epitrochlearis muscle was removed 3 hr later for in vitro incubation. Glycolysis, determined as 3H2O production from [2-3H]-glucose, was increased 45% in muscle taken from endotoxin-treated rats compared to control animals. Glycogen synthesis, assessed by the incorporation of [U-14C]-glucose into glycogen, was similarly elevated. Glycolysis and glycogen synthesis were stimulated by insulin in a dose-dependent manner. Muscles removed from endotoxin-treated rats were slightly more sensitive to insulin, but at the highest dose of insulin used, differences between muscles from control and endotoxemic rats remained similar to differences seen without insulin. Endotoxin-induced changes in glucose metabolism were not reversed by the presence of indomethacin, indicating that prostaglandin production is not responsible for these changes. Thus, endotoxemia results in changes in glucose metabolism in skeletal muscle that are retained in vitro in the absence or presence of insulin.

Animals↗

PubMed1986

Substrate utilization and high energy phosphate levels of hearts from hyperdynamic septic rats.

Experiments were conducted to test the hypothesis that the previously demonstrated depression in ventricular function of rats with hyperdynamic sepsis was a result of depressed high energy phosphate levels or altered myocardial substrate utilization. Rats were inoculated with a pooled fecal homogenate, and 48 hr later their hearts were removed and studied using the Langendorff preparation. The coronaries were perfused with a hydrostatic pressure of 90 mmHg, and hearts were paced at 310-320 beats/min. Substrate oxidation was determined by supplying 14C-labeled glucose, lactate, or palmitate in physiologic concentrations, ie, 5.5, 1, and 0.6 mM, respectively. Hearts were frozen either in situ or after 40-50 min of perfusion for the determination of tissue metabolite levels. Myocardial content of high energy phosphates, total adenine nucleotides, and creatine were similar in septic animals and time-matched controls both in situ and after perfusion. Oxidation of exogenous substrates accounted for the total myocardial O2 consumption in both groups of perfused hearts. Palmitate oxidation was responsible for approximately 50% of the total O2 consumption of the heart, with glucose accounting for approximately 20% and lactate for the remainder. The percentage contribution of the three substrates to oxidative metabolism was similar in hearts from septic and time-matched controls; therefore, myocardial substrate preference was not altered by sustained sepsis. These studies also indicate that ischemia and the concomitant fall in high energy phosphates do not contribute to the myocardial dysfunction of hyperdynamic sepsis.

Adenine Nucleotides↗

PubMed1985

Effects of insulin on glucose metabolism in isolated heart myocytes from adult rats.

The study examined the effect of insulin on glucose metabolism in freshly isolated calcium-tolerant heart myocytes from adult rats. The uptake of 2-deoxyglucose demonstrated an initial lag in response to insulin and the maximal insulin effect was not attained until after 3 min preincubation with the hormone. A dose-response study of 14CO2 production from [14C]glucose revealed that the maximum insulin stimulation of glucose utilization occurred with 5 mU/ml. Both the uptake and the oxidation of glucose proceeded at a linear rate in the absence and presence of insulin. However, insulin exerted a greater effect on the uptake (42-54%) than on the oxidation (17-22%) of exogenous glucose. Incorporation of glucose into glycogen was markedly increased by insulin and resulted in the myocyte glycogen concentration returning to in vivo levels. In the absence of insulin, glucose incorporation plateaued within 10 min of incubation and the glycogen concentration was not altered. Our findings also indicate that at equilibrium, insulin-treated cells exhibited a higher glycogen turnover rate. It thus appears that insulin exerts a differential effect on the different pathways in glucose metabolism in the isolated cardiac cells. This may be related in part to their quiescent state and lower energy demand.

Animals↗

PubMed1985

Glucose kinetics and body temperature after lethal and nonlethal doses of endotoxin.

Rats were injected with doses of endotoxin ranging from 1,000 [lethal dose approximately 50% (LD50)] to 0.01 microgram/100 g, and alterations in hemodynamics, glucose kinetics, and body temperature were studied over the subsequent 4 h. Doses of 10 micrograms/100 g or less were consistently nonlethal over 72 h. Decreases in arterial blood pressure and cardiac output were evident in rats receiving 1,000-10 micrograms/100 g endotoxin. Doses of endotoxin between 1,000 and 10 micrograms produced an early hyperlactacidemia evident by 1 h, whereas the lower doses (1 and 0.1 microgram) induced elevations that exhibited a delayed temporal response. The rates of glucose appearance (Ra) and disappearance (Rd) were increased early and transiently by the higher doses of endotoxin. Lower doses increased glucose Ra and Rd between 2 and 4 h after endotoxin. A febrile response was elicited by 10, 1, and 0.1 microgram/100 g endotoxin, while hypothermia was seen in animals receiving higher doses. Thus high doses of endotoxin induced metabolic and hemodynamic alterations that were temporally associated. Very low nonlethal doses of endotoxin (up to 4 orders of magnitude less than LD50) induced metabolic changes that appeared to be independent of hemodynamic disturbances but were temporally associated with the observed hyperthermia.

Animals↗

PubMed1985

The effect of hyperdynamic sepsis on myocardial performance.

The reviewed studies support the contention that during the high flow or hyperdynamic phase of gram-negative septicemia, cardiac reserve is compromised because of intrinsic myocardial dysfunction. The latter is not referable to coronary hypoperfusion or peripheral pooling or decreased venous return. Although, under resting, nonstressed conditions, indices of myocardial function may appear normal or even elevated, a decreased reserve is evident when additional stress is imposed on the myocardium. Hearts removed from septic rats during the hyperdynamic stage and perfused in vitro (using the isolated perfused working heart preparation) showed a rightward and downward shift in work function curves, indicating a severe depression in cardiac function. Possible mechanisms for the observed dysfunction are discussed. No significant alterations in high energy phosphate production or substrate utilization were observed, indicating that altered myocardial metabolism is not likely to be a significant contributor to the dysfunction. Our results suggest that cardiac dysfunction is partially due to an elevation in the cytosolic calcium concentration which may slow the rate of ventricular relaxation. These studies emphasize that intrinsic cardiac function is depressed early during the course of the septic episode at a time that precedes the onset of circulatory shock.

Animals↗

PubMed1985

Effect of cardiotropic agents on the myocardial dysfunction of hyperdynamic sepsis.

We have previously shown that in vitro myocardial performance is impaired in rats during the hyperdynamic, hypermetabolic phase of sepsis. Although the heart in the resting animal generated an elevated cardiac output, the isolated, perfused heart showed a depressed ventricular function curve. In the present studies, interventions to improve contractile function (increased perfusate calcium concentration or perfusion with ouabain) or to decrease calcium availability to the myofibrils (verapamil and tetracaine) were investigated using the isolated perfused working heart. These studies showed that increasing or decreasing calcium concentration in the perfusion medium had little effect on ventricular performance in the septic group, whereas ouabain enhanced performance by approximately 25%. Addition of verapamil at a dose that caused a minimal decrease in myocardial work (cardiac output X peak systolic pressure) in control hearts showed a 20-25% increase in work in the experimental hearts. Increased levels of verapamil caused a greater depression in myocardial performance in the control hearts than in the hearts from septic rats. Thus, it appears that a multifaceted defect may be present in these hearts with a derangement that can be slightly improved with either ouabain or verapamil. Since neither intervention could completely reverse the myocardial dysfunction in hyperdynamic sepsis, it appears that the defect may be due to other factors in addition to calcium availability for contraction.

Animals↗

PubMed1985

Effects of toxic and nontoxic endotoxin derivatives on glucose kinetics.

Although the polysaccharide portion of bacterial endotoxins (ET) and other components of the bacterial cell wall are known to possess biological activity, the toxic effects produced by ET have been attributed mostly to the lipid-A component. The present study examined the influence of selected gram-negative cell wall components on in vivo carbohydrate homeostasis. Chronically catheterized conscious rats were injected with either ET, lipid A, the White polysaccharide supernatant (WPS-S; polysaccharide-rich and lipid-A-free) or the WPS-precipitate (WPS-P; rich in cell wall components and lipid-A-free) at sublethal doses of 100, 10, and 1 microgram/100 g. The acute hypotensive response to ET and lipid A were similar, while the WPS-P induced a smaller reduction in pressure. Endotoxin, lipid A, or the WPS-P (100 and 10 micrograms) all produced hyperglycemia. Hyperlactacidemia was evident in rats receiving ET, lipid A, and WPS-P; ET-treated animals exhibited the highest lactate concentrations. At the highest doses used, these three fractions increased the rate of glucose appearance. The polysaccharide-rich WPS-supernatant elicited no significant alterations in any of the variables studied. These results indicate that cell wall components of gram-negative bacteria, other than the lipid A of endotoxin, induce changes in carbohydrate metabolism that are similar to those produced by the toxic, lipid-A component of endotoxin.

Animals↗

PubMed1984

Carbohydrate dynamics in the hypermetabolic septic rat.

Glucose turnover is increased during shock and in acute sepsis, but relatively little information is available concerning the regulation of carbohydrate metabolism during the hypermetabolic phase of sepsis. In these studies peritoneal sepsis was induced in rats, following chronic vascular catheterization, by intraperitoneal administration of a pooled fecal inoculum. The resultant peritonitis has been shown to produce a sustained hypermetabolic state during the first three days of infection. Glucose and lactate kinetics were studied using a constant infusion of radiolabeled tracers during the peak of the hypermetabolic phase (day 2). The septic animals exhibited a 42% increase in glucose turnover and a 63% increase in the metabolic clearance rate of glucose, as compared to time-matched control rats. Hepatic glycogenolysis could only contribute 1% to 2% to the increased rate of glucose appearance. A major portion of the elevated glucose turnover was accounted for by a 93% increase in glucose recycling, indicating an enhancement of gluconeogenesis from glucose-derived gluconeogenic precursors. The increased importance of lactate as a precursor for gluconeogenesis in sepsis was indicated by the elevated lactate turnover (34%) and the increased percentage of 14C-glucose derived from 14C-lactate. The insulin to glucagon ratio was decreased in the septic animals as a result of a reduction in the plasma insulin concentration (56%) and an increased glucagon concentration (67%). We conclude that during the hypermetabolic phase of sepsis, the increased peripheral glucose uptake generated more gluconeogenic precursors but did not appear to have a major direct contribution to the increased aerobic metabolism.

Animals↗

PubMed1984

Regulation of substrate oxidation in isolated myocardial cells by beta-hydroxybutyrate.

The role of ketone bodies in myocardial substrate oxidation was examined using freshly isolated Ca2+-tolerant heart myocytes, beta-hydroxybutyrate (beta OHB) inhibited lactate oxidation by the myocytes by 30-60%, and the inhibition was concentration dependent. Palmitate oxidation was also markedly decreased, whereas octanoate oxidation was only minimally affected by the presence of beta OHB. Lactate, octanoate, or palmitate had little, if any, effect on beta OHB oxidation. beta OHB oxidation was reduced by 22-28% in myocytes isolated from chronically diabetic rats, whereas the oxidation of palmitate remained similar to the controls. However, beta OHB still inhibited palmitate oxidation to the same extent as in the control cells. Our data support the role of beta OHB as a physiologic regulator of myocardial substrate metabolism.

3-Hydroxybutyric Acid↗

PubMed1984

Changes in glycerol kinetics after E. coli endotoxin administration in dogs.

The metabolic clearance rate (MCR) and maximal rate of glycerol removal (Rd max) were determined in anesthetized dogs at two time periods after the intravenous administration of either Escherichia coli endotoxin or saline. The nonisotopic method employed in these studies to determine the MCR of glycerol consisted of a constant infusion of glycerol at three different infusion rates. At each infusion rate a steady-state glycerol concentration was obtained. The reciprocal of the slope of the linear relationship between the glycerol infusion rate and the change in the steady-state arterial glycerol concentration was equal to the MCR of glycerol. Administration of endotoxin significantly decreased the MCR of glycerol, whereas the volume of distribution of glycerol was not altered significantly. The arterial glycerol turnover remained unaltered, whereas arterial glycerol concentration increased after endotoxin administration. The studies demonstrate that the elevated arterial glycerol concentration maintained the rate of glycerol turnover in the face of decreased efficiency of glycerol removal after endotoxin administration.

Animals↗

PubMed1984

Cardiac output and redistribution of organ blood flow in hypermetabolic sepsis.

Cardiac output (CO) and the distribution of blood flow were studied in chronically catheterized conscious rats during sustained (4 days) sepsis. Septicemia was induced by intraperitoneal administration of a pooled fecal inoculum, and tissue blood flow and CO were determined daily with 15-micron radioactive microspheres. Mean arterial blood pressure (MABP, 113 +/- 2 mmHg), CO (244.5 +/- 11.4 ml X min-1 X kg-1), and total peripheral resistance (TPR, 1.36 +/- 0.07 mmHg X ml-1 X min) were stable in control rats over the 4 days postinoculation. Septic animals showed a consistent tachycardia with MABP significantly reduced only on days 3 and 4 (86 +/- 4 mmHg). A hyperdynamic response to sepsis was indicated by an elevated CO (27%) and similarly reduced TPR on day 2. The calculated stroke volume averaged 0.22 +/- 0.01 ml/beat and did not vary over time or between the two groups. There was a 40-70% increase in blood flow to the heart, spleen, adrenal glands, and small intestine, and a greater than sixfold increase in hepatic arterial blood flow. The sustained elevation of coronary blood flow, observed in septic animals, was independent of myocardial work and is consistent with impaired myocardial function. Pancreas, stomach, and skeletal muscle blood flow was consistently compromised (24, 39, and 52%, respectively) during sepsis. Blood flow in other organs remained unchanged over time. Sepsis-induced changes in the fractional distribution of blood flow to various organs were similar to those described for absolute flow. (ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1984

Hepatic glycerol flux after E. coli endotoxin administration.

Hepatic glycerol flux was examined in dogs after the administration of Escherichia coli endotoxin (0.4 mg/kg) to determine the contribution of the liver to the previously observed decline in the metabolic clearance rate of glycerol. Hepatic glycerol flux was estimated by determining hepatic arterial and portal venous blood flows with electromagnetic flow probes and by measuring arteriovenous difference of glycerol across the liver. Administration of endotoxin significantly decreased total hepatic blood flow (by approximately 20%) but did not alter hepatic arterial blood flow. Hepatic glycerol clearance decreased by 25-30% after endotoxin administration. Hepatic glycerol extraction also decreased. Under control conditions, 60% of the metabolic clearance rate of glycerol was attributable to the liver, whereas in the postendotoxin state approximately 72% of the glycerol clearance could be accounted for by hepatic clearance. Thus changes in transhepatic glycerol flux are only partially responsible for the previously observed alterations in glycerol clearance after endotoxin administration. Although hepatic glycerol clearance decreased, net hepatic glycerol, as well as lactate and alanine, uptake did not decrease, indicating that gluconeogenic precursor availability to the hepatocytes was not diminished. Hepatic glucose output was elevated after endotoxin administration. Changes in hepatic glucose output and gluconeogenic precursor uptake help explain the endotoxin-induced alternations in the fluxes of these metabolites.

Animals↗

PubMed1984

The effects of acute and chronic diabetes on myocardial metabolism in rats.

This study examined how the duration of experimentally induced diabetes affects myocardial metabolism. Both acutely (2-day) and chronically (30-day and 90-day) streptozocin (STZ)-diabetic rats exhibited hyperglycemia and hyperketonemia, while hyperlipemia was evident only in the chronically diabetic rats. The activity of succinate dehydrogenase was lower, whereas that of 3-hydroxyacyl-CoA-dehydrogenase was higher in the hearts of chronically diabetic rats. Although myocardial concentrations of glucose-6-phosphate, glycogen, and triacylglycerols were elevated in diabetes, the patterns of alterations differed between acute and chronic diabetes. The fructose-1,6-diphosphate/fructose-6-phosphate ratio declined progressively after STZ administration, which was not accompanied by a reciprocal increase in citrate levels, although citrate concentrations were elevated. Impaired glucose oxidation was more severe in the freshly isolated heart cells from 30-day than from 2-day diabetic rats. For a given substrate concentration, the oxidation rates of palmitate and 3-hydroxybutyrate were markedly reduced in myocytes from 30-day diabetic rats. However, they were similar to or even higher than the rates found in their control counterparts under conditions that reflected the respective in vivo concentrations of the substrates. Incubating isolated myocytes from 2-day diabetic rats in the presence of insulin only partially restored the impaired glucose oxidation. Insulin administered to the animals 4 h before the experiments restored the impaired glucose oxidation by the cells. Insulin in vitro or single injection in vivo had little or no effect on glucose oxidation in isolated myocytes from 30-day diabetic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗