Thiol-dependent passive K+-Cl- transport in sheep red blood cells. V. Dependence on metabolism

Measurement of ouabain-insensitive K+ efflux and Rb+ influx in low-K+ sheep red blood cells with artificially altered cellular ATP levels revealed that Cl--dependent K+ transport was activated by N-ethylmaleimide (NEM) in cells with ATP concentrations above 0.5 mM. Depletion of ATP by starvation at 37 degrees C either in glucose-free media for 16 h or in 2-deoxy-D-glucose-containing media for 4 h completely abolished the response of K+-Cl-transport to NEM but did not reduce the basal Cl--dependent K+ flux. On repletion of cellular ATP by a second incubation in media containing glucose, inosine, and inorganic phosphate, the NEM-stimulated K+ (Rb+) flux reappeared. The magnitude of flux reactivation varied directly and monotonically with the ATP level. The data constitute the first unequivocal evidence for a reversible ATP dependence of thiol groups functionally involved in the thiol-dependent K+-Cl- transporter, suggesting that thiol-dependent and volume-sensitive K+-Cl- transport systems are operationally different.

Decrease of [14C]2-deoxyglucose uptake at the intracerebellar nuclei during cerebellar cortex stimulation

The effect of electrical stimulation of the cerebellar cortex at 10-30 c/s on metabolism in the intracerebellar nuclei has been studied using the [14C]2-deoxyglucose method. The experiments, performed on anesthetized or immobilized animals did not produce any detectable changes in the radioautographic labeling of the intracerebellar nuclei compared with controls. Experiments were also performed in animals pretreated with 3-acetylpyridine neurotoxin which selectively destroys the inferior olive and produces an intense labeling of the intracerebellar nuclei. Less marking was observed in restricted regions of the intracerebellar nuclei receiving the axon terminals of the stimulated Purkinje cells if the experiments were done within the first few hours. Following 3-acetylpyridine intoxication, in this early phase, destruction of the inferior olivary cell bodies occurs, but the climbing fibers remain intact. At 2 days or more following 3-acetylpyridine, changes in marking with stimulation could no longer be obtained. The finding is interpreted as being due to an actual reduction of the Purkinje cell activity upon stimulation of the cerebellar cortex, leading to a reduction of the metabolic activity at their presynaptic terminals.

Variations of 1-deoxyglucose(1,5-anhydroglucitol) content in plasma from patients with insulin-dependent diabetes mellitus

The concentration of 1-deoxyglucose(1,5-anhydroglucitol) in plasma from patients with insulin-dependent diabetes mellitus was measured by gas-liquid chromatography with an all-glass capillary column. Twenty-one plasma samples were obtained from 21 patients before insulin therapy, and 34 more from 13 patients receiving insulin therapy. 1-Deoxyglucose was generally not detectable in plasmas of diabetic patients before they received insulin; it was measurable in the patients who had received insulin, although its concentration was low compared with that of healthy subjects. We therefore suggest that the absence of 1-deoxyglucose in plasma is one of the markers of metabolic states of diabetes, perhaps reflecting a disturbed function of carbohydrate metabolism; its presence in plasma within a normal range may reflect the better control of diabetic patients.

A critical appraisal of semi-quantitative analysis of 2-deoxyglucose autoradiograms

Semi-quantitative analysis (e.g. optical density ratios) of [14C]2-deoxyglucose autoradiograms is widely used in neuroscience research. We demonstrate that a fixed ratio of 14C-concentrations in the CNS does not yield a constant optical density ratio but is dependent upon the exposure time in the preparation of the autoradiograms and the absolute amounts of 14C from which the concentration ratio is derived. The failure of a fixed glucose utilization ratio to result in a constant optical density ratio represents a major interpretative difficulty in investigations where only semi-quantitative analysis of [14C]2-deoxyglucose autoradiograms is undertaken.

Metabolic activation of the brachium conjunctivum during induced hypothermia

During hypothermia induced in ground squirrels by the halothane-heliox method, 2-deoxyglucose uptake of a white matter structure, the brachium conjunctivum, increased relative to the surrounding gray matter structures. The possibility of 2-deoxyglucose uptake by glial as well as neuronal elements in the brachium conjunctivum and the implications of this observation for the use of optical density ratios is discussed.

The effect of intranasal zinc sulfate treatment on odor-mediated behavior and on odor-induced metabolic activity in the olfactory bulbs of neonatal rats

This study describes the effect of lesions of the peripheral olfactory receptor sheet on odor-mediated behavior and on odor-induced metabolic activity in the neonatal olfactory bulb. Nine-day-old rats were treated by intranasal irrigation with a solution of 1% ZnSO4 or 5% ZnSO4 or saline. At 1 and 5 days following treatment they were tested for maternally-directed behaviors which are mediated in large part by olfactory cues. At 1 day following treatment the pups treated with ZnSO4 solutions had significant deficits in their odor-directed behavior. By 5 days however, most pups treated with 1% ZnSO4 had recovered to control levels, while the pups treated with 5% ZnSO4 continued to exhibit profound behavioral deficits. Following the behavioral testing, the pups were tested using the 2-deoxyglucose method for amyl acetate odor-induced metabolic activity in their olfactory bulbs. Control pups had large regions of high focal activity in their anterolateral and caudomedial olfactory bulbs. The 1% ZnSO4 pups had smaller foci which were confined primarily to the medial olfactory bulb. The 5% ZnSO4 pups had very little focal uptake in their olfactory bulbs. There was a clear correlation between intact olfactory nerve and glomerular layers and sites of increased functional activity. The results of this study demonstrate that there is a relationship between the degree of behavioral deficit and the extent of odor-induced functional activity in the olfactory bulb.

Acoustic stimulation alters deoxyglucose uptake in the mouse cochlea and inferior colliculus

Deoxyglucose uptake and activities of hexokinase and glucose-6-phosphatase in auditory structures (organ of Corti, stria vascularis and spiral ligament, modiolar section of VIIIth nerve, inferior colliculus) and non-auditory tissues (heart, kidney, liver) of the mouse were analyzed. [3H]Deoxyglucose was given as a pulse into the tail vein and uptake was quantitated by microdissection of tissues and scintillation counting. Radioactivity in cochlear tissues was maximal after 45-60 min and declined with a half-life of 30-60 min. Deoxyglucose 6-phosphate represented ca. 60% of total radioactivity (heart, inferior colliculus, greater than 80%). The ratio of hexokinase to glucose-6-phosphatase activity was considerably lower in the auditory periphery than in brain. The rank order was inferior colliculus much greater than VIIIth nerve approximately equal to heart greater than stria vascularis and spiral ligament greater than kidney greater than organ of Corti approximately equal to liver. Exposure to broadband noise increased glucose utilization in all auditory structures. Uptake was maximally (2- to 3-fold) stimulated at moderate noise intensity (55-85 dBA). In addition, the auditory system showed two salient features: at high intensities (100 and 115 dBA) deoxyglucose uptake decreased from the maximum; and the non-sensory tissues of the cochlea (stria vascularis and spiral ligament) responded to sound parallel to the sensory structures at all levels of stimulus intensity. There were no effects of acoustic stimulation on serum glucose levels, serum kinetics of deoxyglucose, or deoxyglucose uptake into other body tissues.

The relationship of local cerebral glucose utilization to optical density ratios

The validity of optical density ratios used in [14C]2-deoxyglucose neuroanatomical mapping experiments is evaluated by comparing local cerebral glucose utilization (LCGU) and optical density (OD) ratios in the same animals. OD ratios are calculated by dividing the optical density of different gray matter structures by the optical density of a single white matter structure in each animal. OD ratios are linearly related to LCGU within a given animal including stimulated, highly activated regions. Anesthesia profoundly affects the relationship between LCGU and OD ratios, however, showing that OD ratios do not provide an accurate index of LCGU between animals in different physiological states. Anesthesia had only a slight effect on OD ratios, however, indicating that OD ratios may be helpful in assessing whether structures are functionally activated between animals in different physiological states.

2-Deoxyglucose as a substrate for glutathione regeneration in human and ruminant red blood cells

2-Deoxyglucose was found to be a substrate for the regeneration of GSH from GSSG in the red blood cells of humans, sheep, goats and cattle. The regeneration rate with 2-deoxyglucose varied from 15 to 56% of the rate with glucose. It is likely that 2-deoxyglucose is phosphorylated to 2-deoxyglucose-6-phosphate by HK and is then oxidized to 2-deoxygluconate-6-phosphate by G6PD. The latter reaction would produce the NADPH required for GSH regeneration.

Computer assisted analysis of 2-DG autoradiographs

A computerized image processing system is described that assists the neurobiologists in analyzing data from 2-DG autoradiography by providing for: (1) Rapid fine-scale digitization of gray levels using a TV camera (2) The recognition of and verification of subtle differences in optical density with the aid of color windows (3) the superimposition of the autoradiographic image upon the histological image, so that the activity seen in the autoradiograph can be accurately assigned to anatomically defined structures (4) The production of numerical data suitable for statistical analysis and line drawings suitable for black on white publication (5) The relating of local gray level to a norm for the image as a whole, so as to remove the variability introduced by variations in section thickness, in the amount of 2-DG seen by the brain during incorporation, in level of anesthesia, etc. If the localized darkening in autoradiographic images is being used as an index of localized functional activity rather than as a measure of metabolism, normalization obviates the need to obtain arterial blood samples. These routines permit anatomically accurate numerical analysis of autoradiographs without any constraints on the experimental situation.

Mapping of the neural activity in the cerebellum of the mouse during stepping by means of 2-deoxyglucose autoradiography

Incorporation of radioactive 2-deoxy-D-glucose (2-DG) into the cerebellum of mice which were resting in a cage or stepping on a treadmill was examined by means of autoradiography. In the cerebellum of the mouse resting in the cage, a large amount of 2-DG was incorporated into the posterior vermis, the flocculus, cerebellar nuclei and vestibular nuclei. On the other hand, during stepping, incorporation of 2-DG was increased remarkably in the anterior vermis, the pyramis, the anterior part of the ansiform lobule and the paraflcculus, indicating that these regions are functionally involved in locomotor movements.

Regional brain uptake of 2-deoxy-D-glucose following training in a discriminated y-maze avoidance task

Regional brain uptake of 2-deoxy-D-[14C]glucose (2-DG) was measured in mice following training in a discriminated Y-maze avoidance task. In comparison with yoked-control animals that could not escape the footshock, the animals that were trained had decreased uptake of 2-DG in the hippocampus and increased uptake in the striatum. There was no difference in 2-DG uptake between experimental and control animals in the cortex overlying the striatum. Additional control studies showed that 2-DG uptake into the brain was not influenced by ether anesthetization or the route of 2-DG administration (iv or ip). The results of this study indicate that the metabolic activity of regional brain areas following training may reflect the involvement of these structures in learning and memory processes.

Serum 1,5-anhydroglucitol in normal subjects and in patients with insulin-dependent diabetes mellitus

The serum levels of 1,5-anhydroglucitol were measured by gas chromatography in normal subjects and in patients with type 1 (insulin-dependent) diabetes mellitus and compared with those found in some other common diseases. The identity of the compound was checked by thin-layer chromatography and by means of mass fragmentography. The mean level was 81 mumol/l (range 10-146 mumol/l, n = 139) in normal subjects and comparable levels were found in patients with rheumatic disease (n = 20) and in several patients with circulatory diseases. The level was less than 10 mumol/l in 44 patients with insulin-dependent diabetes mellitus, both in newly diagnosed cases and in patients with a long history of the disease with or without nephropathy. The compound did not appear in serum during near normoglycaemic periods elicited by continuous subcutaneous insulin infusion therapy, nor after successful kidney transplantation.

Identification and metabolic implication of 1-deoxyglucose (1,5-anhydroglucitol) in human plasma

1-Deoxyglucose (1,5-anhydroglucitol), a metabolite related to diabetes mellitus, was identified in human plasma by gas-liquid chromatography and by gas-liquid chromatography/mass spectrometry. Plasma polyols were accurately determined with a gas-liquid chromatograph equipped with an all-glass capillary column. The plasma content of 1-deoxyglucose in healthy persons varies with age. Although the precise physiological role of 1-deoxyglucose remains obscure, the method described here for determining the minor polyol components of plasma, as well as the findings of 1-deoxyglucose in the plasma of healthy subjects, may be useful for investigating the metabolic roles of 1-deoxyglucose.

Measurement of cerebral blood flow and metabolism in man

The brain has a high blood now to meet its high obligatory requirement for glucose as a metabolic fuel. Indeed, glucose requirement and blood flow are directly coupled so that the increased metabolic rate during enhanced functional activity of a particular cortical area is associated with increased blood flow. Here a brief review will be given of the most important methods that can be used for the study of cerebral blood flow in human subjects.

Regional cerebral blood flow and glucose metabolism following transient forebrain ischemia

Progressive brain damage after transient cerebral ischemia may be related to changes in postischemic cerebral blood flow and metabolism. Regional cerebral blood flow (rCBF) and cerebral glucose utilization (rCGU) were measured in adult rats prior to, during (only rCBF), and serially after transient forebrain ischemia. Animals were subjected to 30 minutes of forebrain ischemia by occluding both common carotid arteries 24 hours after cauterizing the vertebral arteries. Regional CBF was measured by the indicator-fractionation technique using 4-iodo-[14C]-antipyrine. Regional CGU was measured by the 2-[14C]deoxyglucose method. The results were correlated with the distribution and progression of ischemic neuronal damage in animals subjected to an identical ischemic insult. Cerebral blood flow to forebrain after 30 minutes of moderate to severe ischemia (less than 10% control CBF) was characterized by 5 to 15 minutes of hyperemia; rCBF then fell below normal and remained low for as long as 24 hours. Post-ischemic glucose utilization in the forebrain, except in the hippocampus, was depressed below control values at 1 hour and either remained low (neocortex, striatum) or gradually rose to normal (white matter) by 48 hours. In the hippocampus, glucose utilization equaled the control value at 1 hour and fell below control between 24 and 48 hours. The appearance of moderate to severe morphological damage in striatum and hippocampus coincided with a late rise of rCBF above normal and with a fall of rCGU; the late depression of rCGU was usually preceded by a period during which metabolism was increased relative to adjacent tissue. Further refinement of these studies may help identify salvageable brain after ischemia and define ways to manipulate CBF and metabolism in the treatment of stroke.

Alterations in local cerebral glucose utilization during hemorrhagic hypotension in the rat

The alterations in local cerebral glucose utilization in 58 anatomically discrete regions which occur during a period of hemorrhagic hypotension have been investigated in conscious rats, using the quantitative autoradiographic 14C-deoxyglucose technique. Hemorrhagic hypotension (mean arterial pressure reduced by approximately 50 mm Hg) effected significant increases in glucose utilization in eight areas of the central nervous system, namely, the nucleus of the tractus solitarius (glucose utilization increased by 38%), the dorsal motor nucleus of the vagus (by 36%), locus coeruleus (by 38%), lateral habenular nucleus (by 40%), periventricular nucleus of the hypothalamus (by 41%), paraventricular nucleus of the hypothalamus (by 97%), supraoptic nucleus (by 86%), and the interstitial nucleus of the stria terminalis (by 84%). In five of these eight areas (nucleus of the tractus solitarius, dorsal motor nucleus of the vagus, paraventricular and supraoptic nuclei, and the interstitial nucleus of the stria terminalis), a significant relationship could be demonstrated between the level of glucose utilization and mean arterial blood pressure. In the majority of the CNS regions examined (neocortex, hippocampus, thalamus, extrapyramidal and motor areas), hemorrhagic hypotension was without significant effect upon local cerebral glucose utilization. The results provide direct evidence of the functional involvement of specific brain areas of conscious rats (thus obviating complicating anesthetic influences) in the response of the CNS to hemorrhagic hypotension.

Auditory stimulation alters the pattern of 2-deoxyglucose uptake in the inner ear

The 2-deoxy-D-glucose (2-DG) autoradiographic technique was adapted for application to the inner ear. The uptake of [14C]-DG during silence was compared with that observed during exposure to wide band noise (WBN) or pure tones at an intensity level of 85 db SPL. In silence, the highest levels of 2-DG uptake were observed in the spiral ligament, spiral prominence and stria vascularis, with approximately equal levels of uptake in each structure. The high levels of 2-DG uptake observed in the ligament and prominence are surprising, and suggest a more active role for these structures in cochlear function than has previously been suspected. Levels of uptake in the organ of Corti, spiral ganglion and VIIIth nerve were much lower, although well above background. During exposure to WBN, 2-DG uptake increased markedly in the VIIIth nerve, and spiral ganglion throughout the cochlea, and in the organ of Corti in the lower basal turn. 2-DG uptake did not change significantly in the spiral ligament or stria vascularis. During pure tone exposure, increased 2-DG uptake was noted in localized regions of the VIIIth nerve and spiral ganglion.

The effect of free radical derived hydroxyeicosatetraenoic acids on hexose transport in the human polymorphonuclear leukocyte

The following racemic hydroxyicosatetraenoic acids were prepared and assayed for their ability to stimulate hexose transport in human polymorphonuclear leukocytes: 15-, 12-, 11-, 9-, 8-, and 5-hydroxyicosatetraenoic acids. The compounds were isolated from reduced, autoxidized arachidonic acid. The results demonstrate that only the 12- and 5-hydroxyicosatetraenoic acids are biologically active inducing half-maximal responses at 820 and 176 nM, respectively. Thus, the bioactions of hydroxicosatetraenoates ae crucially dependent upon the position of the hydroxy residue. Response to both hydroxyicosatetraenoates was effectively blocked by two inhibitors of arachidonic acid metabolism: nordihydroguaiaretic acid and indomethacin. A third arachidonic acid antimetabolite, 5, 8, 11, 14-eicosatetraynoic acid, completely inhibited the response to 12-HETE but caused only partial inhibition of the response to 5-HETE.

Local cerebral blood flow and glucose consumption of rats with experimental gliomas

Experimental brain tumors were produced in rats by intracerebral implantation of a neoplastic glial cell clone. Within 2–6 weeks, spherical brain tumors developed at the implantation site with a mean diameter of 6 mm. Local blood flow and local glucose utilization were measured under light barbiturate anesthesia by quantitative autoradiography in the tumor and peritumoral brain tissue. In solid parts of the tumor, blood flow was 57.8 ± 2.0 ml/100 g/min (mean ± SE), and glucose utilization was 87.2 ± 5.8 μmol/100 g/min, respectively. In necrotic regions, flow and glucose utilization were zero. In peritumoral brain tissue of the ipsilateral hemisphere blood flow was reduced by 13–23%, as compared to homologous regions of the opposite side, the greatest decrease being recorded in the ipsilateral thalamus. Flow in the opposite hemisphere was of the same order of magnitude as in normal control rats. Glucose consumption, in contrast, was distinctly reduced in both hemispheres: in the cortex and putamen, it was 40–50% lower than in normal controls. The following conclusions are drawn: (1) during tumor development the high glucose consumption in the tumor tissue is not coupled to an equal increase in blood flow; (2) peritumoral cerebral blood flow decreases on the ipsilateral but not on the contralateral side, and (3) the metabolic rate of glucose is distinctly inhibited in both hemispheres of tumor-bearing animals. The dissociation between blood flow and metabolism suggests that metabolic inhibition is not the consequence of a diaschitic depression of functional activity.

Brain functional activity during PAG stimulation-produced analgesia: a 2-DG study

The autoradiographic 2-deoxyglucose method for regional cerebral metabolic activity was modified for use with tritium label to determine which brain stem and spinal cord nuclei changed their functional neural activity during periaqueductal gray stimulation-produced analgesia. The greatest changes in activity during electrical stimulation of the periaqueductal gray occurred in nucleus paragigantocellularis, the ventral portion of the nucleus reticularis gigantocellularis, and the nucleus cuneiformis. Substantial increases in metabolic activity were also evident in the spinal trigeminal nucleus and the substantia gelatinosa. Many of the regions which displayed increased functional activity in the present study have been shown to possess substantial enkephalin immunoreactivity. While several of these structures have previously been implicated in modulation of nociceptive transmission, this study raises the possibility that other brain stem nuclei may also participate in analgesic mechanisms.

F-18-labeled 3-deoxy-3-fluoro-D-glucose for the study of regional metabolism in the brain and heart

Glucose is the major physiological substrate of the brain and an important physiological substrate for the myocardium. [19F]fluoro-3-deoxy-glucose [3-FDG(F-18)] was studied to determine whether it is a suitable tracer for evaluating the metabolic function of the brain and myocardium. 3-FDG(F-18) was rapidly accumulated in the mouse myocardium (10-12% injected dose/g) and remained constant up to 120 min. Blood, liver, and lung activities exhibited a rapid accumulation of activity (4% injected dose/g) at 1 min, followed by elimination of activity up to 30 min (2% injected dose/g), and then remaining unchanged for a period of 120 min. The arterial blood curve in the dog was fit best by three exponential components (T 1/2 = 0.52 min, 2.75 min, and 142.8 min). Transverse-section images were obtained of the dog's brain and myocardium. From sequential two-dimensional images, a clearance half-time of 26.88 min was determined for the canine brain. Radiation doses for man were calculated from tissue distribution data for mice.

Role of the adenylate cyclase system in altered insulin release from islets of Langerhans of aging rats

In attempting to understand the causes of the hyperglycaemia observed in aging populations and to determine the mechanism(s) for the diminished in vitro insulin release from islets of Langerhans of older rats, the adenylate cyclase-cyclic AMP system was studied in isolated islets from 12 month old and 2 1/2 month old (control) male rats to determine its role in this altered insulin secretion. Islets of Langerhans were isolated by collagenase digestion and then either incubated in the presence of low or high concentrations of glucose for studies of insulin release or were sonicated and assayed for determinations of activities of adenylate cyclase and phosphodiesterase. Insulin release was identical from islets of 12 month old and 2 1/2 month old rats to 2.8 mM D-glucose, while in the presence of 16.7 mM D-glucose, insulin release was decreased by 33% (P less than 0.02) from islets of the older animals. Adenylate cyclase activity was diminished by 60% (P less than 0.005) from the 12 month old rats as compared with islets from the 2 1/2 month old controls, while low Km phosphodiesterase activity was similar in islets from both groups of animals. From these studies it appears that the adenylate cyclase-cyclic AMP system may play a role in the altered insulin release from islets of aging rats.

Role of Ca2+ and Mg2+ in neutrophil hexose transport

The influence of extracellular Ca2+ and Mg2+ on the transport of 2-deoxy-[3H]glucose into human polymorphonuclear neutrophils was studied. Omission of these cations from the cell suspensions had little effect on resting hexose uptake. Furthermore, the addition of the bivalent cation chelator, EDTA, depressed uptake only slightly. Similarly, neither cation was essential for the enhanced 2-deoxy-D-[3H]glucose uptake stimulated by two chemotactic factors (C5a and N-formylmethionylleucylphenylalanine) and arachidonic acid: enhanced uptake was only partially depressed by the omission of Ca2+ and Mg2+ from the suspensions and was still prominent in the presence of EDTA. Two other neutrophil stimulants, the ionophores, A23187 and ionomycin, also enhanced hexose uptake but their actions were heavily dependent upon extracellular bivalent cations and were totally abrogated by EDTA. In all instances, extracellular Ca2+, but not Mg2+, supported optimal enhanced hexose transport induced by stimuli. Activation of 2-deoxy-D-[3H]glucose uptake by each of the five stimuli was totally blocked by cytochalasin B (a blocker of carrier-mediated hexose transport) and D-glucose but not by L-glucose. The data indicate, therefore, that a variety of neutrophil stimulants activate carrier-mediated hexose transport. Although this transport can be triggered by the movement of extracellular Ca2+ into the cell (as exemplified by the action of the two ionophores), such Ca2+ movement is not required for the actions of chemotactic factors or arachidonic acid. Other mechanisms, such as a rearrangement of intracellular Ca2+, may be involved in mediating the activation of hexose transport induced by the latter stimuli.

Regional brain glucose utilization following intrastriatal injections of kainic acid

Regional brain glucose utilization following intrastriatal injections of kainic acid (KA) was studied by [14C]deoxyglucose autoradiography. In halothane anesthetized rats intrastriatal injections of 0.5-1.9 nmol KA produced histological lesions characterized by neuronal necrosis and glial reaction which varied in volume from approximately 3 to 25 cu. mm. These lesions were restricted to the striatal injection site. Intrastriatal injections of 3.8 nmol led to large lesions in striatum but also in ipsilateral hippocampus, pyriform cortex, entorhinal cortex, and amygdaloid nuclei. Injection doses of 0.5-3.8 nmol KA produced a large increase in striatal glucose utilization within 1 h; 7 days after injections however, glucose utilization was reduced below control levels in a dose-dependent manner. In addition to striatum there were large transient increases in glucose utilization in deep layers of frontal cortex, substantia nigra pars reticulata, ventral tier nuclei of thalamus, and lateral septum. Each of these structures bear close physical or synaptic proximity to the striatal injection site. Also, structures far distant from the striatal injection site exhibited large, transient, dose-dependent increases in glucose utilization; these regions included hippocampus, pyriform cortex, entorhinal cortex, and amygdaloid nuclei. There was a close correlation between the development of areas of neuronal necrosis and a reduction in glucose utilization. These results suggest that intrastriatal injections of KA may cause metabolic and perhaps electrical activation not only of structures near or synaptically connected to the injection site, but also of far distant, but particularly 'sensitive' brain structures probably by diffusion of small amounts of drug. The occurrence of neuronal death in limbic structures after injections of relatively high doses of KA into striatum may result from prolonged firing in those circuits which continues without the prolonged presence of KA.

Phosphorus nuclear magnetic resonance of bovine platelets

31P nuclear magnetic resonance (NMR) spectra of bovine platelets at 28 degrees C display prominent peaks from adenine nucleotides in two different environments, the metabolic and storage pools. Addition of 20 mM 2-deoxy-D-glucose and 0.1 mM 2,4-dinitrophenol depletes metabolic ATP, resulting in loss of nucleotide signals at 5, 10, and 19 ppm and leaving peaks at 6.5, 10.5, and 19 ppm that are assigned primarily to the dense granule storage pool. The ATP/ADP concentration ratio of the remaining pools is 1.9 +/- 0.2, with chemical shifts which reflect a more acidic environment for the intragranular nucleotides than for the cytosol. Isolated bovine dense granules give spectra with similar peak positions to those ascribed to the storage pool after metabolic depletion of whole cells. Storage pool nucleotide spectra are highly temperature dependent. Below 20 degrees C, the beta-ATP peak broadens and decreases in area to the point that it is almost undetectable at 0 degrees C, probably reflecting formation of progressively higher molecular weight aggregates at the lower temperatures. The release reaction was followed by 31P NMR after addition of thrombin at 28 degrees C. Spectra of the cell suspension taken at 5-min intervals were compared to spectra of perchloric acid extracts produced in parallel. A new finding of these experiments is that the released nucleotides rapidly undergo a transition to a "NMR silent" form as part of the bovine platelet release reacton. Metabolic breadkdown and external paramagnetic ion interactions did not explain the loss of signal from the storage pool. During release reaction, the nucleotides may be broadened out beyond detection due to immobilization by divalent cation and/or platelet membrane binding.

Influence of dopaminergic systems on the lateral habenular nucleus of the rat

The alterations in glucose utilization in the lateral habenular nucleus following the systemic administration of a putative dopaminergic agonist and antagonist have been examined in 48 rats by means of the autoradiographic 2-deoxyglucose technique. The administration of apomorphine (0.15--5 mg/kg) resulted in significant dose-dependent reductions (by 25 +/- 5% following 0.5 mg/kg) in glucose utilization in the lateral habenula. Haloperidol administration (0.01--10 mg/kg) was associated with increased (by 46 +/- 17% with 0.1 mg/kg) glucose utilization in the lateral habenula. The effects of apomorphine upon metabolic activity in the lateral habenula can be prevented by the prior administration of haloperidol (0.1 mg/kg). These observations provide evidence that metabolic activity in the lateral habenula, a nucleus occupying a strategic position between the forebrain and the mesencephalon, may be regulated by the activity in dopaminergic systems.

Effects of ageing on local rates of cerebral glucose utilization in the rat

The effects of ageing on local rates of glucose utilization in 47 brain structures in resting conscious rats have been examined. Three age groups have been studied: young adult (4 to 6 months), middle-aged (14 to 16 months), and aged (26 to 36 months). The results show that ageing per se is associated with decreases in rates of glucose utilization in specific brain regions. The decreases were not progressive with age, probably because of the influence of a survival effect. Age-related pathological changes are known to occur in some of the brain structures in which decreases in rates of glucose utilization were found. Selective decreases were also found in the caudate-putamen, the parietal cortex and in structures associated with vision and audition. In these latter structures the changes may reflect reductions in local functional activity, perhaps due to decreased sensory input from the primary sensory organs.

The effect of somatostatin on pancreatic endocrine responses mediated via the parasympathetic innervation in the conscious calf

1. The effect of somatostatin on the responses to moderate insulin hypoglycaemia and to 2-deoxyglucose has been examined in 2--3 week-old calves with cut splanchnic nerves. 2. Intravenous infusions of somatostatin (150 p-mole . kg-1 . min-1) completely suppressed release of glucagon, pancreatic polypeptide (PP) and insulin from the pancreas in response to 2-deoxyglucose (1.1 m-mole/kg I.V.). 3. The same dose of somatostatin completely blocked the rise in plasma PP concentration that normally occurs in response to moderate insulin hypoglycaemia and significantly delayed the rise in plasma pancreatic glucagon concentration. The hypoglycaemic response to insulin was also found to be intensified by the administration of somatostatin. 4. It is concluded that each of the pancreatic neuroendocrine responses, that are now known to be mediated via the parasympathetic innervation, is suppressed in the presence of somatostatin in the young calf.

Age-associated changes in deoxyglucose uptake in whole brain

Cerebral blood flow, studied by means of a diffusible indicator, remains unchanged in the aging process (developmental changes). On the contrary, brain activity, evaluated by deoxyglucose uptake, is significantly reduced. Papaverine, which increases cerebral blood flow, and vincamine, slightly but significantly, act on this parameter in the older animals.

Mapping of local cerebral functional activity by measurement of local cerebral glucose utilization with [14C]deoxyglucose

A method has been developed to measure the rates of glucose utilization in the individual structural and functional components of the central nervous system. It can be applied to conscious as well as anaesthetized animals. The method is based on the use of [14C]deoxyglucose as a tracer for glucose consumption. [14C]Deoxyglucose-6-phosphate accumulates in the tissue in a mathematically definable relationship to the rate of the tissue's glucose utilization. The [14C]deoxyglucose-6-phosphate concentrations in the various tissues of the nervous system are measured by a quantitative autoradiographic technique. The autoradiographs themselves are pictorial representations of the relative rates of glucose consumption in these tissues. Application of this method to rats and monkeys in various states of altered function demonstrates a clear and close relationship between the local levels of functional activity and energy metabolism. The method appears to be useful for mapping functional neural pathways on the basis of evoked metabolic responses (Plum, Gjedde and Samson, 1976).

An alternative synthesis of 4-deoxy-4-fluoro-D-glucose and its transport in the human erythrocyte

Treatment of methyl 4-O-mesy-alpha-D-galactopyranoside with benzyl bromide in N,N-dimethylformamide in the presence of silver oxide yielded methyl 2,3,6-tri-O-benzyl-4-O-mesyl-alpha-D-galactopyranoside which with tert-butylammonium fluoride at reflux underwent nucleophilic displacement to give methyl 2,3,6-tri-O-benzyl-4-deoxy-4-fluoro-alpha-D-glucopyranoside. This compound on hydrogenolysis provided crystalline methyl 4-deoxy-4-fluoro-alpha-D-glucopyranoside (9). The structure of 9 was established by its conversion to the 2,3,6-tri-O-acetyl derivative and by n.m.r. and m.s. analysis. Acid hydrolysis of 9 gave 4-deoxy-4-fluoro-D-glucose (1). A modification of an established synthesis of 4-deoxy-D-xylo-hexose (2) from methyl 2,3,6-tri-O-benzoyl-alpha-D-galactopyranoside is described. A systematic comparison was made of the transport parameters (Kx and Vmax) of D-glucose, 2, and 1 in human erythrocytes. The Kx values observed for the above sugars are: 4.0mM, 4.5mM, and 4.6mM, respectively. These results indicate that O-4 in beta-D-glucopyranose is not involved in hydrogen bonding to the carrier protein associated with the transport of D-glucose in the erythrocyte.

Mouse brain deoxyglucose uptake after footshock, ACTH analogs, alpha-MSH, corticosterone or lysine vasopressin

The cerebral uptake of subcutaneously injected [3H]2-deoxy-D-glucose (2DG) in 16 brain regions was examined following 30 noncontingent random footshocks or the acute injection of saline, ACTH1-24 (0.5 microgram/g), ACTH/MSH4-10 (0.25 microgram/g), [D-Phe7]ACTH4-10 (0.25 microgram/g), [Met4SO2,D-Lys8,Phe9]ACTH4-9 (0.01 microgram/g), ALPHA-MSH (0.5 microgram/g), corticosterone (2.5 microgram/g) or lysine vasopressin (0.05 microgram/g). Footshock selectively decreased 2DG uptake in parietal cortex and brain stem, and increased that in the hypothalamus. Whole brain 2DG uptake was decreased by injection of saline or most of the hormones relative to uninjected animals, but this effect was probably peripheral since plasma glucose content was increased by the injections. The only regionally specific effect of the hormones was an increased 2DG uptake in olfactory bulb by saline, ACTH/MSH4-10 And corticosterone relative to uninjected animals. Since alpha-MSH had been reported previously to decrease blood flow (measured by antipyrene uptake) in all brain regions except occipital cortex [5,6], we directly compared antipyrene uptake with 2DG uptake in the same animals using a double-isotope procedure. The results revealed an increase in 2DG uptake relative to antipyrene in cortical regions relative to subcortical regions, contradicting earlier assumptions [19].

Guanosine triphosphate catabolism in human and rabbit erythrocytes: role of reductive deamination of guanylate to inosinate

The reductive deamination of guanylate to inosinate was demonstrable but occurred at low rates in human and rabbit erythrocytes incubated in vitro with or without glucose. However, the process was considerably accelerated in erythrocytes incubated with deoxyglucose. In human erythrocytes incubated with deoxyglucose, deamination was the major pathway of catabolism of guanylate; little or no guanylate was dephosphorylated. In rabbit erythrocytes, guanylate was both deaminated and dephosphorylated. Inosinate formed from guanylate was metabolized only by dephosphorylation in human erythrocytes, but in rabbit erythrocytes, it was also converted to xanthylate.

Existence of only a single functional pool of adenosine triphosphate in human erythrocytes

The question of whether separate "membrane" and "soluble" pools of ATP exist in erythrocytes has been examined. Phosphoglycerate kinase (EC 2.7.2.3)-derived ("membrane") ATP was labeled by short-term incubation with inorganic [32P]phosphate. Pyruvate kinase (EC 2.7.1.40)-derived ("soluble")ATP is not labeled under these circumstances. The specific activity of the gamma-phosphate of "soluble" ATP was then evaluated by the addition of 2-deoxyglucose and measurement of the specific activity of 2-deoxyglucose-6-[32P]phosphate formed. This specific activity was essentially the same as the overall specific activity of erythrocyte ATP gama-phosphate, indicating that no functional pools of phosphoglycerate kinase-derived and pyruvate kinase-derived ATP exist in erythrocytes.

Dose dependent reduction of glucose utilization by pentobarbital in rat brain

A new method of determining the rate of glucose utilization in brain regions of individual rats has been used to measure the dose dependency of the reduction of the metabolic activity of the cerebral cortex by pentobarbital. Cerebral cortical glucose utilization is depressed to a basal level of 44% of the control rate when cerebral pentobarbital levels exceed 50 microgram per g of tissue. The major portion of this effect occurs between the cerebral pentobarbital range of 10--20 microgram per g, which can be achieved by 1/5 to 1/10 the normal anesthetic intraperitoneal dosage. If a depression of brain metabolism is responsible for the previously reported protection of the brain from ischemic damage, these data suggest a substantial reduction of brain metabolic rate is achieved in the rat at a barbiturate dosage which may be therapeutically relevant in the human after acute brain ischemia.

Human toxic neutrophils. IV. Incorporation of amino acids and uptake of 2-deoxy-D-glucose

Toxic neutrophils were studied for incorporation of amino acids into total proteins and for uptake of a glucose analogue. Both the amino acid incorporation and the uptake of 2-deoxy-D-glucose were increased in toxic neutrophils. This finding may indicate an alteration in the cell membrane of toxic neutrophils.