Effect of an amino group at carbon 2 of 1-deoxyglucose analogues on anorexia in the rat

A steric hindering group at carbon 2 of 1-deoxyglucose analogues was introduced by epimerization, deoxidation and substitution of a hydroxyl group with either an acetamido or a fluoro group. Injection of this analogue into the rat third cerebroventricle attenuated the feeding suppression produced by 1-deoxyglucose. In contrast, the replacement of a hydroxyl group at carbon 2 with an amino group produced anorexia of the same magnitude as that produced by 1-deoxyglucose. Amination at carbon 2 was more potent than that at carbon 3, 4 or 6. These results indicate that an amino group at carbon 2 of the glucose molecule is important to reinforce the feeding suppression caused by 1-deoxyglucose analogues.

[Monolayer culture of pancreatic islet cells of the adult rat: effect of 2-deoxy-2-fluoroglucose]

In the present study, the culture system for preparing monolayer islet cells of the neonatal rat was applied and modified for use with the pancreas of the adult rat. In this procedure, whole pancreatic tissues were enzymatically dispersed and then cultured for 30 days in TCM 199 medium with either 5.5 mM glucose or 5.5 mM glucose plus 1 mM 2-deoxy-2-fluoroglucose. Under culture conditions without 2-deoxy-2-fluoroglucose, the responsiveness of B cells was totally abolished by day 20 of culture. The addition of 2-deoxy-2-fluoroglucose destroyed fibroblasts selectively in a period of 20 days, yielding the monolayers mostly consisting of islet cells, and the morphological characteristics were well preserved at the end of the culture study period. After culture for 20 days in medium with 2-deoxy-2-fluoroglucose, insulin secretion was raised in a dose-dependent fashion due to the increasing concentrations of glucose, leucine and 2-ketoisocaproate. The dose-response curve for insulin secretion evoked by glucose was sigmoid with a Km of 7 mM glucose, and the secretion threshold was observed at a concentration of between 2.8 and 5.5 mM glucose. The ratios of the maximum level to the basal were 6, 5 and 3 respectively for glucose, leucine and 2-ketoisocaproate. The secretory competence was preserved in the B cells on day 30 as well. Addition of epinephrine or clonidine inhibited the glucose-induced insulin secretion dose-dependently. At a concentration of 10(-7) M, both drugs produced an 80% drop in insulin secretion evoked by glucose. The inhibitory effect of epinephrine or clonidine was reversed by 3 X 10(-5) M yohimbine or 10(-5) M phentolamine, whereas 10(-5) M propranolol had little or no effect and alpha adrenergic blockade of prazosin (5 X 10(-5) M) was weak as compared to that of yohimbine. At a high concentration (10(-5) M) of phenylephrine, a marked drop of insulin secretion was observed. In summary, the present culture system facilitates the establishment of monolayers of adult rat pancreas that consist mostly of islet cells. In addition, it is certain that the response of the B cells in 2-deoxy-2-fluoroglucose to nutrient secretagogues and the adrenergic modulation of insulin secretion are well preserved for a long-term culture period of 30 days. These preparations may provide a useful tool not only for the in vitro study of the B-cell function, but also for use in implantation resource.

[2-Deoxyglucose as a tool for analyzing the humoral component of the cardiovascular reaction to stress]

Blood pressure (BP), heart rate (HR), adrenaline (A) and noradrenaline (NA) effects of 2-desoxyglucose (500 mg/kg i.v.) were studied in conscious chronically instrumented wistar rats. A and NA contents in the blood were estimated by HPLC with electrochemical detection. In 15-40 minutes after 2-DG administration it was 13-16-fold increase in A content, 1.7-1.9-fold increase in NA content. At the same time BP fell by 5 mm Hg and HR fell by 100 beats/min. Atropine blocked bradycardia but had no effect on BP. It is concluded that high levels of endogenous A during stress are not responsible for cardiovascular responses usually observed.

Little or no induction of hyperglycemia by 2-deoxy-D-glucose in hereditary blind microphthalmic rats

Studies were made on whether hereditary microphthalmic rats (1), which are congenitally blind, showed a hyperglycemic response to intracerebroventricular injection of 2-deoxy-D-glucose (2DG) in their subjective light period. In contrast to previous findings in normal rats in which 2DG injection caused light-cycle dependent hyperglycemia (2) and bilateral lesion of the suprachiasmatic nucleus (SCN) completely abolished this hyperglycemia (3), 2DG injection caused no and only slight hyperglycemia in male and female rats with hereditary microphthalmia, respectively. Gross and histological examinations indicated that these rats had no optic nerve or retinohypothalamic tract and that their SCN had an abnormal structure. Locomotive activity recordings showed that all the blind rats had a free-running circadian activity rhythm. These findings suggest that the projection sites of the retinohypothalamic tract to the SCN are involved in the mechanism of the hyperglycemic response to 2DG, but that neural cells, which may be responsible for the generation of circadian rhythms, are not. We have reported that when adult rats were blinded by orbital enucleation, their hyperglycemic response to 2DG was suppressed temporarily 3-5 weeks after the operation, but that their plasma insulin level was basically higher and increased further after 2DG injection during this period (4). In congenitally blind rats, however, the basal plasma insulin level was not higher and the level did not change after 2DG treatment. This difference is discussed from the view point of the role of the premature SCN in regulation of the plasma insulin concentration.

2-Deoxy-D-glucose-induced central glycopenia differentially influences renal and adrenal nerve activity in awake SHR rats

2-deoxy-D-glucose (2-DG) evokes an increase in the efferent discharge rate of the adrenal nerve in narcotized rats and rabbits. The study reported here was undertaken to determine the sympathetic nerves and blood pressure responses to i.v. 2-DG administration in awake SHR rats. An increase in adrenal sympathetic nerve activity (adrSNA) by 63% was observed 15 min after 125 mg/kg 2-DG administration, but there were no changes in the renal sympathetic nerve activity (renSNA), blood pressure (BP) or the heart rate (HR). Additional administration of 375 mg/kg 2-DG (cumulative dose was 500 mg/kg) led to the increase in the adrSNA by more then 120%, and in BP by 20 mm Hg, whereas renSNA was increased only by 30%. These results indicate that 2-DG-induced neuroglycopenia evokes highly differential changes in adrenal and renSNA in awake SHR rats. Whether this explains the marked response in BP in SHR to 2-DG is to be established.

Complex regulation of heat shock- and glucose-responsive genes in human cells

We have isolated a human genomic clone that encodes the glucose-responsive protein GRP78 and have used this cloned gene probe, together with a cloned HSP70 gene, to study the expression of both stress-induced genes in response to inhibitors of cellular metabolism. On the basis of the effects of this group of chemicals on GRP78 and HSP70 expression, we have identified three classes of stress gene inducers. The first class induces GRP78 expression and includes inhibitors of glycoprotein processing. The second class results in coordinate activation of both GRP78 and HSP70 synthesis and includes amino acid analogs and heavy metals. Chemicals in the third class coordinately induce GRP78 and repress HSP70 expression; this class includes the calcium ionophore A23187 and the glucose analog 2-deoxyglucose. Whereas induction of GRP78 or HSP70 expression is primarily due to transcriptional activation, chemicals that repress HSP70 expression act through posttranscriptional regulation. These results reveal that the regulation of GRP78 and HSP70 expression is complex and may be dependent on the specificity and magnitude of physiological damage.

Effect of insulin and 2-deoxy-D-glucose on feeding and plasma glucose levels in the spiny mouse

Adult male spiny mice (Acomys cahirinus) were challenged with 2-deoxy-D-glucose (2-DG) or regular insulin, and food intake or plasma glucose concentration was measured. Mice did not increase their food intake over baseline levels following treatment with 2-DG (62.5-1000 mg/kg). In contrast, regular insulin injections (1-50 U/kg) stimulated a modest, but significant increase in feeding, which was apparent within 2 hr at a low dose of 1 U/kg. However, a marked hyper- and hypoglycemia (compared to saline controls), respectively, were induced within 30 min by 2-DG (250 and 500 mg/kg) and regular insulin (1 and 3 U/kg). Reduced glucose levels may not account for the insulin-induced hyperphagia.

Conditioned taste aversion produced by 2-deoxy-D-glucose in rats and hamsters

The glucose antimetabolite 2-deoxy-D-glucose (2DG) reliably causes hyperphagia in rats, but has consistently proven ineffective in producing overeating in golden hamsters. It was hypothesized that hamsters do not overeat following 2DG administration because of unusually strong aversive effects of the drug in this species. To test this hypothesis, rats and hamsters were tested in a conditioned taste aversion (CTA) paradigm, in which a novel 0.1% saccharin solution was paired on three occasions with intraperitoneal injections of either saline, lithium chloride (LiCl; 50 mg/kg), or 2DG (either 350 or 750 mg/kg). CTA was measured in 16 twenty-minute, two-bottle preference tests which were conducted at 2-3 day intervals following conditioning. LiCl and 2DG both produced strong and long-lasting aversions to saccharin solution in rats. However, 2DG was significantly less effective than LiCl in producing CTA in hamsters. It is unlikely, therefore, that the failure of 2DG to produce hyperphagia in hamsters is due primarily to an unusual sensitivity to the aversive effects of the drug.

A cytochemical study on the effects of energy deprivation on autophagocytosis in Ehrlich ascites tumor cells

The effect of energy deprivation on autophagocytosis in Ehrlich ascites tumor cells was studied using cytochemical techniques. Autophagocytosis was induced with vinblastine incubation (0.1 mM) and the cellular ATP-level was lowered with 2-deoxy-D-glucose (0.35 mM). Acid phosphatase was used as a marker for lysosomal enzymes and imidazole-buffered osmium tetroxide impregnation in order to study the effects of energy deprivation on the maturation of autophagic vacuole (AV) membranes. Control and vinblastine treated cells maintained their ATP-levels throughout the incubation period tested (120 min). 2-Deoxy-D-glucose alone and with vinblastine decreased the intracellular ATP-level significantly after only 3 min incubation. Most of the AV's in control and vinblastine treated cells contained degraded material and acid phosphatase activity. Their membranes were stained only slightly or not at all with imidazole-buffered osmium tetroxide. 2-Deoxy-D-glucose alone as well as with vinblastine induced in particular an accumulation of early stages of AV's. These vacuoles contained undegraded cytoplasmic material and no acid phosphatase activity and their membranes were stained usually partly with imidazole-buffered osmium tetroxide. The membranes of some early AV's resembled endoplasmic reticulum and still had attached ribosomes. It was concluded that the inhibition of cellular energy production used in the present study did not inhibit autophagic sequestration but retarded the maturation of AV membranes and impaired the functioning of lysosomal hydrolases.

Temporary suppression of the hyperglycemic response to 2-deoxy-D-glucose by blinding

Studies were made on whether there is a time-dependency in the hyperglycemic response to intracranial injection of 2-deoxy-D-glucose (2DG) in blind rats. 2DG was given to blind rats in their subjective light and dark periods to see if the response free-runs like their circadian locomotor and feeding rhythms. The following results were obtained: (1) In control period and week 3 after blinding, 2DG caused greater hyperglycemia in the subjective light period than in the subjective dark period; (2) In weeks 4 and 6, however, 2DG caused only slight hyperglycemia, while it caused considerable hyperinsulinemia in both the subjective light and dark periods with no time-dependency. (3) In week 8, the hyperglycemic response to 2DG was completely restored while the hyperinsulinemic response was lost. These findings indicate that the subjective time-dependency in the hyperglycemic response to intracranial injection of 2DG exists until week 3 and after week 8 after blinding, however, in week 4 and 6 after blinding the subjective time-dependency appeared to disappear and the hyperglycemic response is largely suppressed in association with hyperinsulinemia. Together with a previous finding that bilateral lesions of the SCN completely abolished the response to 2DG and the fact that blind rats showed circadian rhythms of feeding and locomotive activity even in weeks 4 and 6 after blinding, these findings present the possibility that the site responding to 2DG is in the vicinity of the SCN, but is in different neuronal cells from those of the circadian oscillator. However, it is also possible that the blinding elicits the suppression of hyperglycemia due to 2DG through disturbing neural pathway outside the SCN which control blood glucose concentration.

Differential growth inhibition of human diploid fibroblasts by 2-deoxyglucose and antimycin A with ageing in vitro

The relative growth inhibitory effects of 2-deoxyglucose and antimycin A were monitored at five stages during the life-span in vitro of human diploid fibroblasts. A marked age-dependent response was observed with 2-deoxyglucose but not with antimycin A. The results confirm an increase in the rate of glycolysis with ageing, which appears to be independent of cellular mitochondrial respiratory chain capacity. This may be associated with reduced utilization of the hexose monophosphate shunt and a consequent decline in the availability of ribose moieties for nucleic acid biosynthesis.

Nervous control of gastric and pancreatic secretory response to 2-deoxy-D-glucose in the dog

The relative contribution of the vagus and splanchnic nerves as mediators of the action of 2-deoxy-D-glucose (2-DG) on the stomach and the pancreas is largely unknown. In conscious dogs with gastric and pancreatic fistulas, the effect of 2-DG (100 mg kg-1, given as an intravenous bolus) on gastric acid and pancreatic exocrine secretion was tested before and after bilateral truncal vagotomy and after truncal vagotomy plus celiac and superior mesenteric ganglionectomy (i.e. extrinsic denervation of the stomach and the pancreas). In another set of dogs, only ganglionectomy was performed and the same experiments were done as in the first set of dogs. With the extrinsic nerves intact, 2-DG caused a rapid (within 15 min) and prolonged increase in gastric acid output as well as in pancreatic flow rate, bicarbonate and protein output. Truncal vagotomy abolished the gastric acid and pancreatic secretory response to 2-DG; additional ganglionectomy had no further effect. Ganglionectomy alone did not significantly alter 2-DG-stimulated gastric acid output, pancreatic flow rate and bicarbonate output; protein output, however, was significantly diminished by 57%. These results indicate that (a) intravenous 2-DG is a potent stimulant of gastric acid and pancreatic bicarbonate and protein output; (b) the vagus nerves are the major mediators of the gastric and pancreatic secretory response to 2-DG; (c) the sympathetic nerve fibers running through the celiac and superior mesenteric ganglia are probably not involved in the mediation of the 2-DG-induced gastric acid and pancreatic bicarbonate secretion. The diminished protein response to 2-DG after ganglionectomy is probably due to cut vagal fibers running through these ganglia.

Patterns of increased and decreased ingestive behavior after injections of lithium chloride and 2-deoxy-D-glucose

In previous research, 750 mg/kg 2DG yielded a number of effects suggesting a postdrug nausea; and the present experiments revealed that the illness-inducing agent LiCl similarly produced taste aversion learning at 7.5 mg/kg, inhibited drinking in water-deprived animals at 30 mg/kg, depressed feeding in hungry rats at 60 mg/kg, and evoked food intake and pica at 120 mg/kg. The appearance of eating and pica at the same dosage suggested that rats may eat food as well as a nonnutritive substance as a species-specific reaction to illness and that postdrug feeding, including that observed after 2DG, is an insufficient condition for concluding that a treatment produces no internal distress. A liquid diet that reportedly ameliorates the glucoprivic feeding deficits produced by lateral hypothalamic and zona incerta lesions theoretically could produce its effects if lesions made rats more reactive to 2DG-induced malaise and if this diet were more palatable to animals experiencing internal distress. However, this liquid diet failed to facilitate food intake after LiCl, nor did it reduce the inhibited eating produced by LiCl in food-deprived subjects. Liquid diet effects in lesioned animals, therefore, may not be explained by factors related to a 2DG-induced malaise.

Maintenance of pancreatic endocrine cells of neonatal rats: effect of 2-deoxyglucose on insulin biosynthesis

The relationship between insulin biosynthesis and proinsulin mRNA activity was examined in pancreatic monolayer cultures of the neonatal rat. Monolayer cultures were maintained in TCM 199 medium containing 16.7 mM of either glucose or 2-deoxyglucose or in a basal medium not containing glucose for 24 hr. The fractions containing mRNA extracted from these cultures were translated in a cell-free protein synthesizing system of rabbit reticulocyte lysate. The proinsulin mRNA activity was determined by the radioactivity of the translation product immunoprecipitated using anti-insulin serum, and identified as preproinsulin with a molecular weight of 11,500 on gel electrophoresis. The amount of insulin biosynthesis was determined by the incorporation of [3H]-leucine into (pro)insulin. In islet B cells cultured in a medium with 16.7 mM glucose, insulin biosynthesis induced by 16.7 mM glucose was enhanced by 158% when cultured in basal medium without glucose. This increment corresponded nicely with a 185% increase in the proinsulin mRNA activity. However, the addition of 16.7 mM 2-deoxyglucose to the basal medium resulted in a 293% increase in glucose-induced insulin biosynthesis despite a 16% drop in the proinsulin mRNA activity, and primed a dose-dependent increase of insulin biosynthesis over the concentration range of 0 to 16.7 mM glucose. These results suggest first that in neonatal B cells insulin biosynthesis may be regulated at the transcriptional level, and second, that 2-deoxyglucose may cause the transition of the neonatal B cell to an adult-type response.

Membrane glycoproteins are involved in the differentiation of the BC3H1 muscle cell line

The nonfusing muscle cell line BC3H1 expresses a family of muscle-specific proteins when the fetal bovine serum (FBS) concentration is reduced from 20 to 1%. We have used a series of glycosylation inhibitors to assess the role played by glycoproteins in the initiation of differentiation in this cell line. Tunicamycin (TNM) and 2-deoxy-D-glucose, added to cells when the FBS concentration was reduced, blocked creatine phosphokinase (CPK) induction by 70-95%. These effects were dose dependent and reversible. TNM and 2-deoxy-D-glucose also reversed CPK induction in differentiated cells. Leupeptin and N-acetylglucosamine did not reverse these effects. 1-Deoxynojirimycin, 1-deoxymannojirimycin, and swainsonine have no effect on induced CPK expression, whereas castanospermine, a glucosidase I inhibitor, blocked its induction completely. As attempts to use conditioned medium from cells grown in 1 or 20% FBS have no effect on this differentiation process we conclude that high mannose structures, but not complex form glycoproteins, bound to the surface of BC3H1 cells play a role in transducing signals for differentiation and are probable mediators of cell/cell contact.

Maintenance of neonatal rat B cells in glucose-depleted medium: a perifusion study

Two groups of monolayer cultures of pancreatic cells from the neonatal rat were maintained in glucose-depleted TCM 199 medium, supplemented with 5.5 mmol galactose/l, with or without 0.1 mmol 2-deoxyglucose/l. Another group was kept in medium with 5.5 mmol galactose/l alone, following exposure for 2 days to a medium with 5.5 mmol galactose/l and 10 mumol iodoacetic acid/l to kill fibroblasts selectively. Each of these monolayers was cultured in a perifusion system for a total of 7 days so that phasic insulin secretion could be compared. On day 0, B cells responded in a monophasic fashion to acute challenge with 16.7 mmol glucose/l whereas, in the presence of 10 mumol forskolin/l and 1 mmol 3-isobutyl-1-methyl-xanthine/l, the same dose of glucose stimulated a biphasic response of approximately the same magnitude. At a concentration of 10 mmol/l, leucine and 2-ketoisocaproate both produced only minimal increase in the second phase of secretion above the basal level. No response to secretagogues was seen under culture conditions without 2-deoxyglucose. In contrast, addition of 2-deoxyglucose to the galactose-supplemented medium stimulated B cells to secrete insulin in a biphasic fashion in response to a single dose of glucose, and the stimulatory effects of leucine and 2-ketoisocaproate were also remarkably increased. Moreover, when exposed to a linear concentration gradient of glucose, leucine or 2-ketoisocaproate, these B cells responded to secretagogues in a dose-dependent fashion.(ABSTRACT TRUNCATED AT 250 WORDS)

Norepinephrine release from PVN and lateral hypothalamus during perfusion with 2-DG or insulin in the sated and fasted rat

Both insulin and 2-deoxy-D-glucose (2-DG) when given systemically to the rat modify the activity of noradrenergic systems in different regions of the animal's hypothalamus. The purpose of the present investigation was to ascertain whether the nutritional status of the animal would serve to influence the pattern of efflux of norepinephrine (NE) from sites in the hypothalamus perfused with either 2-DG or insulin. Permanent guide cannulae were first implanted stereotaxically above the paraventricular nucleus (PVN) or lateral hypothalamus (LH). Following recovery from surgery, each rat was either satiated with food or deprived of food for 20-22 hr with water always freely available. Then 0.1 microCi of [3H]-NE was micro-injected into the intended site of perfusion in a volume of 1.0 microliter. After 15 min had elapsed, the site was perfused repeatedly with an artificial CSF at a rate of 20 microliters/min. At the mid-point of successive 5.0 min perfusions, either 10 micrograms/microliter 2-DG or 4.0 mU/microliters porcine insulin was incorporated into the CSF perfusate. Thereafter, an additional set of 3-4 samples of perfusate was collected. When perfused in the PVN of the satiated rat, 2-DG significantly enhanced the efflux of [3H]-NE, whereas in the fasted animal insulin tended to suppress the output of the catecholamine. Conversely, at sites of perfusion in the LH, insulin evoked the release of [3H]-NE when the rat was fasted, whereas 2-DG tended to induce mixed effects on the release of [3H]-NE under both sated and fasted conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Dissociation of adenosine triphosphate levels and contractile function in isovolumic hearts perfused with 2-deoxyglucose

Addition of 2-deoxyglucose (DG, 8 to 13 mM) to a perfusate containing 5 mM pyruvate as oxidizable substrate caused gradual decline of contractile function of Langendorff-perfused isovolumic rat heart. Simultaneously 31P-NMR spectra showed accumulation of 2-deoxyglucose-6-phosphate (DG-6P) and decrease in phosphocreatine (PCr) and ATP contents; inosine appeared in high concentration in perfusate leaving heart. Subsequent reperfusion of the heart with DG-free solution resulted in the recovery of contractile function and PCr (to 75%), as well as in slow decay of DG-6P at unchanged low level of ATP (35%). No correlation was found between tissue ATP content and contractile function, when expressed as the product of developed pressure and heart rate. In contrast, contraction correlated with tissue PCr level at low ATP. These data demonstrate that effective contraction of the isovolumic heart is possible at substantially decreased level of cytoplasmic ATP. The results of this study are in accord with a concept of ATP compartmentation in cardiac cells.

The mechanism of 2-deoxy-glucose-induced insulin secretion in the mouse

1 Intravenous injection of 2-deoxy-glucose (3 mmol/kg) increases plasma levels of insulin and glucose in the mouse. This study investigated the contribution of various autonomic receptors to the plasma insulin response. 2 Pretreatment with the cholinergic antagonist methylatropine abolished the response completely. 3 Pretreatment with the alpha-adrenoceptor antagonist phentolamine caused a potentiated response, whereas the beta-adrenoceptor antagonist L-propranolol had no effect. 4 Pretreatment with methylatropine and phentolamine combined caused a small insulin response, which was inhibited by propranolol. 5 Pretreatment with the nicotonic antagonist hexamethonium abolished the response. 6 It is concluded that 2-deoxy-glucose induces a stimulation of insulin secretion in vivo in the mouse predominantly by a cholinergic mechanism. 7 2-Deoxy-glucose also activates alpha-adrenergic mechanisms which affect the size of the insulin secretory response. beta-Adrenoceptor and non-adrenergic, non-cholinergic mechanisms seem to be less important.

Site of action of anorectic drugs: glucoprivic- versus food deprivation-induced feeding

Feeding induced by 2-deoxyglucose was compared with feeding induced by food deprivation in terms of antagonism by anorectic drugs and of anatomical site of action. Glucoprivic feeding was completely blocked by microinjection of amphetamine, fenfluramine, and mazindol into the paraventricular nucleus of the hypothalamus (PVN). Deprivation-induced feeding was not blocked by amphetamine, fenfluramine, or mazindol microinjected into the PVN. Neither the feeding induced by 2-deoxyglucose nor its reversal by amphetamine were blocked by pretreatment with the beta-adrenergic antagonist, propranolol. Amphetamine and fenfluramine blocked both glucoprivic- and deprivation-induced feeding when microinjected into the perifornical region of the lateral hypothalamus. These data suggest that food consumption induced by 2-deoxyglucose treatment can be antagonized by anorectic drugs acting at recognition sites present in several hypothalamic nuclei, while deprivation-induced feeding acts through different receptor mechanisms which may be specific to the perifornical region of the lateral hypothalamus.

Modification of the radiation induced damage by 2-deoxy-D-glucose in organ cultures of human cerebral gliomas

Effects of a glucose antimetabolite, 2-deoxy-D-glucose (2-DG), on the gamma ray induced radiation damage have been studied in organ cultures of human cerebral gliomas. Percentage of cells with micronuclei (M-fraction) was used to assay the radiation damage. Experimental data indicate the following results. Untreated cerebral gliomas show considerable spatial heterogeneity in M-fraction; In spite of this heterogeneity, increases in M-fraction induced by gamma rays can be clearly observed, if multiple and randomly selected explants are analyzed for each group; The radiation induced M-fraction in different gliomas varies over a wide range; Presence of 2-DG (5 mM) for 4 h after irradiation leads to an increase in the radiation induced M-fraction in the majority of tumors, while in a smaller number (congruent to 25%) a decrease is observed under similar conditions. These results can be explained on the basis of a model postulating differential effects of 2-DG on the energy linked modulations of the processes of repair and fixation of DNA damage, which competitively influence the formation of micronuclei.

Dual effects of 2-deoxyglucose on synthesis of the glycoprotein hormone common alpha-subunit in butyrate-treated HeLa cells

Sodium butyrate (Btr) (3 mM) causes a 10-fold increase in production of the glycoprotein hormone alpha-subunit in HeLa cells. The following report demonstrates that this response could be inhibited about 95% by 5 mM 2-deoxy-D-glucose (dGlc), whereas alpha-subunit production in uninduced cells was affected little or not at all. Addition of D-mannose restored the Btr induction of Hela-alpha in cultures that had been treated with dGlc. When the alpha-subunits secreted by cells cultured in Btr plus dGlc or in Btr alone were compared by gel filtration (Sephadex G-75) and lectin affinity (concanavalin A and ricin) chromatography, differences were noted that probably reflect changes in their carbohydrate moieties. Immunoprecipitation of [35S]methionine-labeled HeLa-alpha and incubation with endoglycosidase H indicated that the subunit secreted from cells in the presence of dGlc contained oligosaccharide side chains that were not processed to the complex type. Cells that were simultaneously treated with Btr plus dGlc showed no increase in alpha-subunit production over cells receiving Btr only; in contrast, cells that were preincubated with Btr for either 16 or 36 h before dGlc was added exhibited high levels of subunit synthesis. Measurement of alpha-mRNA levels at various times after Btr and dGlc were added to cultures indicated that Btr brought about a dramatic increase in alpha-specific mRNA about 24 h after being added to cultures. This increase could be prevented by dGlc when added simultaneously with Btr but not when added after a 24-h preincubation. Although dGlc prevented the induction of alpha-subunit and alpha-mRNA in response to Btr, it had no effect on histone hyperacetylation, suggesting that if this chromatin modification is necessary for the induction process, it is not in itself sufficient. Together, the data demonstrate that dGlc inhibits the accumulation of alpha-subunit mRNA normally produced in response to Btr and that the subunit produced contains altered oligosaccharide constituents.

Small dose of 2-deoxy-D-glucose completely excludes the overgrowth of fibroblasts

The present work has been undertaken to assess the effects of a small dose of 2-deoxy-D-glucose on proliferation of fibroblasts in culture by morphological criteria. Fibroblasts in culture medium with 2-deoxy-D-glucose proliferated only to a slight degree, but cell confluence was not achieved. They became swollen and the cytoplasm was increasingly occupied by lucent area. These changes became prominent on the 10th day of incubation. When cell mixtures of fibroblasts and TYK-nu (cell line of undifferentiated adenocarcinoma of the ovary) or TYK-nu only were incubated under the influence of 2-deoxy-D-glucose, the degenerative changes aforementioned were observed only in fibroblasts, while no significant changes were ascertained in the cell line of the cancer by morphological criteria. These results suggest that a small dose of 2-deoxy-D-glucose shows considerable promise in specific inhibition of fibroblastic proliferation during the process of establishing the cell line of the cancer.