Glucose-rich Diet Research Articles

Zein nanoparticles extend lifespan in C. elegans and SAMP8 mice

Empty zein nanoparticles (NP) have been shown to lower glycemia in rats by stimulating the secretion of endogenous GLP-1. This study evaluated the effect of these nanoparticles on the lifespan of two animal models: C. elegans fed with a glucose-rich diet and the senescence accelerated mouse-prone 8 (SAMP8 mice). In C. elegans, NP increased the mean lifespan of worms by 7 days (from 17.1 for control to 24.5 days). This observation was in line with the observed significant reductions of glucose and fat contents, lipofuscin accumulation, and ROS expression. Furthermore, NP supplementation led to an upregulation of the expression of daf-16 and skn-1 genes. DAF-16 (orthologue of the FOXO family) and SKN-1 (orthologue of mammalian Nrf/CNC proteins) are implicated in activating detoxification mechanisms against oxidative damage. In SAMP8, oral administration of NP also extended the mean lifespan of mice (by 28 % compared to controls), corroborating the protective effect of these nanoparticles.

The impact of glucose on mitochondria and life span is determined by the integrity of proline catabolism in Caenorhabditis elegans

Mutations in genes involved in mitochondrial proline catabolism lead to the rare genetic disorder hyperprolinemia in humans. We have previously reported that mutations of proline catabolic genes in Caenorhabditis elegans impair mitochondrial homeostasis and shorten life span, and that these effects surprisingly occur in a diet type-dependent manner. Therefore, we speculated that a specific dietary component may mitigate the adverse effects of defective proline catabolism. Here, we discovered that high dietary glucose, which is generally detrimental to health, actually improves mitochondrial homeostasis and life span in C.elegans with faulty proline catabolism. Mechanistically, defective proline catabolism results in a shift of glucose catabolism toward the pentose phosphate pathway, which is crucial for cellular redox balance. This shift helps to maintain mitochondrial reactive oxygen species homeostasis and to extend life span, as suppression of the pentose phosphate pathway enzyme GSPD-1 prevents the favorable effects of high glucose. In addition, we demonstrate that this crosstalk between proline and glucose catabolism is mediated by the transcription factor DAF-16. Altogether, these findings suggest that a glucose-rich diet may be advantageous in certain situations and might represent a potentially viable treatment strategy for disorders involving impaired proline catabolism.

Erythritol: An In-Depth Discussion of Its Potential to Be a Beneficial Dietary Component.

The sugar alcohol erythritol is a relatively new food ingredient. It is naturally occurring in plants, however, produced commercially by fermentation. It is also produced endogenously via the pentose phosphate pathway (PPP). Consumers perceive erythritol as less healthy than sweeteners extracted from plants, including sucrose. This review evaluates that perspective by summarizing current literature regarding erythritol's safety, production, metabolism, and health effects. Dietary erythritol is 30% less sweet than sucrose, but contains negligible energy. Because it is almost fully absorbed and excreted in urine, it is better tolerated than other sugar alcohols. Evidence shows erythritol has potential as a beneficial replacement for sugar in healthy and diabetic subjects as it exerts no effects on glucose or insulin and induces gut hormone secretions that modulate satiety to promote weight loss. Long-term rodent studies show erythritol consumption lowers body weight or adiposity. However, observational studies indicate positive association between plasma erythritol and obesity and cardiometabolic disease. It is unlikely that dietary erythritol is mediating these associations, rather they reflect dysregulated PPP due to impaired glycemia or glucose-rich diet. However, long-term clinical trials investigating the effects of chronic erythritol consumption on body weight and risk for metabolic diseases are needed. Current evidence suggests these studies will document beneficial effects of dietary erythritol compared to caloric sugars and allay consumer misperceptions.

High-Glucose Diet Attenuates the Dopaminergic Neuronal Function in C. elegans, Leading to the Acceleration of the Aging Process.

Parkinson’s disease (PD) is a neurodegenerative disease characterized by the selective degeneration of neurons, primarily in the substantia nigra. Environmental or exogenous factors that cause Parkinson’s disease have not been sufficiently elucidated. Our study aims to investigate the causative effect of a high-glucose diet on Parkinson’s disease-relevant dopaminergic neuronal system in Caenorhabditis elegans. Aging parameters were first observed by measuring the lifespan, body movement, and body sizes with and without the background of high glucose. The toxic effect of a high-glucose diet was further explored by observing the dopaminergic neurons using transgenic Pdat-1::gfp strains, BZ555, under a Zeiss microscope, and the experiments were extended by assessing dopamine-related behavioral analysis including basal slowing response and alcohol avoidance. The aggregation of the α-synucleins was also assessed by observing the NL5901 mutants. Worms fed with 250 mM glucose showed daf-2-independent regulation of aging, displaying a short lifespan (≤15 days), long body size (max. 140%), and slow movement (min. 30%, 10 bends/min). Anterior dopaminergic neurons were rapidly inactivated (70%) by a glucose-rich diet from 12 h of exposure, suggesting specific degeneration in ADE neurons. The dysregulation of neurons led to deteriorations in dopaminergic behaviors including basal slowing response (BSR). A high-glucose diet decreased dopamine synthesis (40 pg/mg vs 15 pg/mg protein) and induced α-synuclein aggregation in the muscles. Results demonstrate the potential of a high-glucose diet as a trigger of dopaminergic neuronal dysregulation conjugating aging acceleration.

Efficacy of Glucose Starvation of Cancer Cells in the Progress of Oral Squamous Cell Carcinoma Induced in Hamster.

Oral squamous cell carcinoma (OSCC) is the most common form of oral cancer, showing poor prognosis and high mortality. Meanwhile, cancer metabolism is an essential contributor to its progression and response to treatment. This research aims to investigating the effect of a glucose-rich and glucose-free diet on the progress of oral squamous cell carcinoma induced in hamsters. forty Syrian Hamsters were incubated in two groups. The first one consisted of twenty hamsters, in which the carcinogenic material (DMBA) was applied in the buccal pouch of the hamster three days per week with a glucose-rich diet). The second one was composed of twenty hamsters, in which the carcinogenic material (DMBA) was applied in the buccal pouch three days per week with a glucose-free diet). Hamsters in both groups were sacrificed in groups of five hamsters at a time and at intervals (two weeks, six weeks, ten weeks, and Fourteen weeks). A histological study was performed after conventional staining with hematoxylin and eosin was done. After two weeks of the experiment hyperplasia, mild dysplasia, and moderate dysplasia were recorded in hamster buccal pockets with a glucose-rich diet, and after six weeks moderate dysplasia, severe dysplasia, and carcinomas in situ were recorded, after ten weeks severe dysplasia, carcinomas in situ, and OSCC, after fourteen weeks OSCC were recorded. While with a glucose-free diet Hyperkeratosis, hyperplasia, and mild dysplasia were observed after a two-week the experiment, after six weeks, mild dysplasia, moderate dysplasia, and severe dysplasia were recorded, after ten weeks, moderate dysplasia, severe dysplasia, and carcinoma in situ, after fourteen weeks Severe dysplasia, carcinoma in situ, and OSCC were reported. our results showed that a glucose-free diet slightly prevents oral squamous cell carcinoma, It may be a supportive treatment in addition to conventional cancer treatment.

The effect of capromorelin on glycemic control in healthy dogs

Capromorelin is a ghrelin-receptor agonist widely used as an appetite stimulant in dogs. Capromorelin disrupts glucose homeostasis in cats but information regarding its effects on canine glucose homeostasis is lacking. The study objective was to evaluate the effect of capromorelin on glucose homeostatic mechanisms in healthy dogs. Eight clinically healthy client-owned adult dogs were enrolled in this prospective, cross-over, placebo-controlled study. Dogs were randomized to receive capromorelin (Entyce, 3 mg/kg) or placebo, q24h for 3 d. A wk later, treatments were crossed over. Interstitial glucose (IG) concentrations were measured using a flash glucose monitoring system throughout. On d 1 of each treatment, blood glucose (BG), insulin, glucagon, glucose-dependent insulinotropic peptide (GIP), and glucagon-like peptide-1 (GLP-1) concentrations were measured before drug administration, then before and 30–120 min after feeding a glucose-rich diet (Ensure Plus, 21 kcal/kg). Data were analyzed as a 2-period crossover design using generalized least squares estimation. Capromorelin administration increased mean 48 h IG by10% and mean BG by 20% at 90 and 120 min post-prandially (P < 0.0001). Post-prandially, there was a time-by-treatment effect for insulin (P = 0.03) and GIP (P = 0.0002) because capromorelin doubled geometric mean insulin concentrations at 120 min and increased geometric mean GIP concentrations more rapidly than after placebo. There were no differences in glucagon or GLP-1 concentrations between treatment groups. The increase in post-prandial blood glucose was not the result of overt suppression of incretin hormone secretion. There was also no suppressive effect of capromorelin on insulin.

Glucose tolerance of iguanas is affected by high-sugar diets in the lab and supplemental feeding by ecotourists in the wild.

There is great interspecific variation in the nutritional composition of natural diets, and the varied nutritional content is physiologically tolerated because of evolutionarily based balances between diet composition and processing ability. However, as a result of landscape change and human exposure, unnatural diets are becoming widespread among wildlife without the necessary time for evolutionary matching between the diet and its processing. We tested how a controlled, unnatural high glucose diet affects glucose tolerance using captive green iguanas, and we performed similar glucose tolerance tests on wild Northern Bahamian rock iguanas that are either frequently fed grapes by tourists or experience no such supplementation. We evaluated both short and longer-term blood glucose responses and corticosterone (CORT) concentrations as changes have been associated with altered diets. Experimental glucose supplementation in the laboratory and tourist feeding in the wild both significantly affected glucose metabolism. When iguanas received a glucose-rich diet, we found greater acute increases in blood glucose following a glucose challenge. Relative to unfed iguanas, tourist-fed iguanas had significantly lower baseline CORT, higher baseline blood glucose, and slower returns to baseline glucose levels following a glucose challenge. Therefore, unnatural consumption of high amounts of glucose alters glucose metabolism in laboratory iguanas with short-term glucose treatment and free-living iguanas exposed to long-term feeding by tourists. Based on these results and the increasing prevalence of anthropogenically altered wildlife diets, the consequences of dietary changes on glucose metabolism should be further investigated across species, as such changes in glucose metabolism have health consequences in humans (e.g. diabetes).

Fuzhuan Tea protects Caenorhabditis elegans from glucose and advanced glycation end products via distinct pathways

Abstract Fuzhuan Tea (FZT) protects against obesity and obesity-related disorders. However, little is known about its effects on high-sugar toxicity in Caenorhabditis elegans. Here, we find that FZT limits the life-shortening effects of a high-sugar (glucose, sucrose, galactose, and fructose) diet, but does not extend lifespan on a normal diet or protect against oxidative stress. FZT also can prolong healthspan and alleviate the detrimental effects of a glucose-rich diet. Furthermore, we report that effects of FZT on glucose toxicity and advanced glycation end products (AGEs) damage can be dissociated. Notably, FZT is dependent on DAF-16/FOXO and the insulin/IGF-1 signaling (IIS) pathway to promote lifespan and decrease fat content on a glucose-rich diet; concomitantly, FZT reduces AGEs levels by regulating SKN-1/Nrf and p38/mitogen-activated protein kinase (MAPK) pathway, independent of DAF-16/FOXO and IIS pathway. Our findings indicate that FZT protects against high glucose toxicity by a mechanism other than protection against AGEs damage.

Mitochondrial complex I bridges a connection between regulation of carbon flexibility and gastrointestinal commensalism in the human fungal pathogen Candida albicans.

Efficient assimilation of alternative carbon sources in glucose-limited host niches is critical for colonization of Candida albicans, a commensal yeast that frequently causes opportunistic infection in human. C. albicans evolved mechanistically to regulate alternative carbon assimilation for the promotion of fungal growth and commensalism in mammalian hosts. However, this highly adaptive mechanism that C. albicans employs to cope with alternative carbon assimilation has yet to be clearly understood. Here we identified a novel role of C. albicans mitochondrial complex I (CI) in regulating assimilation of alternative carbon sources such as mannitol. Our data demonstrate that CI dysfunction by deleting the subunit Nuo2 decreases the level of NAD+, downregulates the NAD+-dependent mannitol dehydrogenase activity, and consequently inhibits hyphal growth and biofilm formation in conditions when the carbon source is mannitol, but not fermentative sugars like glucose. Mannitol-dependent morphogenesis is controlled by a ROS-induced signaling pathway involving Hog1 activation and Brg1 repression. In vivo studies show that nuo2Δ/Δ mutant cells are severely compromised in gastrointestinal colonization and the defect can be rescued by a glucose-rich diet. Thus, our findings unravel a mechanism by which C. albicans regulates carbon flexibility and commensalism. Alternative carbon assimilation might represent a fitness advantage for commensal fungi in successful colonization of host niches.

Glucose-rich diet aggravates monocrotophos-induced dopaminergic neuronal dysfunction in Caenorhabditis elegans.

The present study aimed to obtain insights into the mechanism(s) by which glucose-rich diet aggravates monocrotophos (MCP)-induced dopaminergic neuronal dysfunction in Caenorhabditis elegans. In this study, we exposed three different strains of worms (wild-type N2, CB1112 (cat-2(e1112)II, tyrosine hydroxylase-deficient mutant, catecholamine absent) and the transgenic BZ555 (egls1-dat-1p::green fluorescent protein [GFP]) (in which bright GFP is tagged to the dopamine neuronal soma and processes) grown and maintained in normal nematode growth medium or 2% glucose enriched-nematode growth medium to MCP (0.75 mm) for 48 h. After the exposure, dopamine-mediated behaviors such as repulsion to nonanone, chemotaxis index and basal slowing response were determined in worms. Dopamine, 3,4-dihydroxy phenyl acetic acid and homovanillic acid content were quantified in N2 worms. The extent of neurodegeneration was visualized and quantified in dat-1::GFP worms. Basal slowing response study clearly indicated that cat-2 worms exposed to MCP and glucose were less affected compared to N2 of the same treatment. Learning and memory were affected by MCP and glucose. While MCP-treated worms showed lesser repulsion to nonanone compared to control worms, MCP-treated, glucose-fed worms showed a greater reduction in repulsion to nonanone. Further, MCP-treated, glucose-fed worms exhibited a marked reduction in dopamine content and an increase in 3,4-dihydroxy phenyl acetic acid and homovanillic acid levels compared to that in control. Dat-1::GFP showed a significant degeneration of dopaminergic neurons when exposed to glucose and MCP. Thus, our results clearly demonstrate that glucose-rich diet aggravates the dopaminergic neuronal dysfunction induced by MCP in C. elegans. Copyright © 2016 John Wiley & Sons, Ltd.

SREBP and MDT-15 protect C. elegans from glucose-induced accelerated aging by preventing accumulation of saturated fat.

Glucose-rich diets shorten the life spans of various organisms. However, the metabolic processes involved in this phenomenon remain unknown. Here, we show that sterol regulatory element-binding protein (SREBP) and mediator-15 (MDT-15) prevent the life-shortening effects of a glucose-rich diet by regulating fat-converting processes in Caenorhabditis elegans. Up-regulation of the SREBP/MDT-15 transcription factor complex was necessary and sufficient for alleviating the life-shortening effect of a glucose-rich diet. Glucose feeding induced key enzymes that convert saturated fatty acids (SFAs) to unsaturated fatty acids (UFAs), which are regulated by SREBP and MDT-15. Furthermore, SREBP/MDT-15 reduced the levels of SFAs and moderated glucose toxicity on life span. Our study may help to develop strategies against elevated blood glucose and free fatty acids, which cause glucolipotoxicity in diabetic patients.

Fructose alters adiponectin, haptoglobin and angiotensinogen gene expression in 3T3-L1 adipocytes

Fructose- or sucrose-rich diets can cause insulin resistance and increase the risk of cardiovascular disease. Adipokines are correlated with the development of these diseases in obesity. We hypothesize that fructose and sucrose induce insulin resistance via effects on adipokine gene expression in adipocytes. This study analyzed the effect of fructose or glucose on adiponectin, haptoglobin, and angiotensinogen gene expression in 3T3-L1 adipocytes. Ten days after differentiation, the cells were pretreated with serum- and glucose-free medium. Twenty-four hours later, fructose or glucose (0, 5, 10, or 20 mmol) was added into the medium, and the cells were collected after a further 24 hours. Adiponectin, haptoglobin, and angiotensinogen gene expression were determined. Adiponectin gene expression increased when 10 or 20 mmol glucose was added compared with that observed for the non-hexose-treated cells. A similar effect occurred when 5 mmol fructose was added. Glucose (10 mmol) and fructose (20 mmol) stimulated haptoglobin gene expression in 3T3-L1 adipocytes compared with 0 mmol, with glucose producing a more pronounced effect. Although 20 mmol fructose caused an increase in angiotensinogen gene expression, glucose did not. In conclusion, in this study of 2 hexoses revealed an increase in adiponectin gene expression, suggesting that the effect of a glucose-rich diet on the development of insulin resistance is not related to the effect of these hexoses on adipocyte adiponectin gene expression. However, insulin resistance and cardiovascular disease promoted by fructose-rich diets could be partially related to the effect of fructose on adiponectin and angiotensinogen gene expression.

Spot 14 protein interacts and co-operates with chicken ovalbumin upstream promoter-transcription factor 1 in the transcription of the L-type pyruvate kinase gene through a specificity protein 1 (Sp1) binding site.

In hepatocytes, the amount of the Spot 14 (S14) protein is closely related to the full expression of enzymes involved in the glycolytic and lipogenic pathways. In the present study we address the role played by this protein in the control of transcription of the L-type pyruvate kinase (L-PK) gene in primary hepatocytes. We show that human S14, which by itself does not bind to the L-PK promoter, physically interacts with the human chicken ovalbumin upstream promoter-transcription factor 1 (COUP-TF1) and induces the switch of this factor from a repressor to an activator. However, the enhancing activity of S14 and COUP-TF1 depends on the presence of a proximal GC-rich box (the L0 element) that specifically binds nuclear proteins from the livers of rats fed a glucose-rich diet. Moreover, the L0 element, which strongly binds dephosphorylated specificity protein 1 (Sp1), loses all affinity when this factor is phosphorylated by cAMP-dependent protein kinase. Mutations that affect binding of Sp1 and nuclear proteins to the L0 box also decrease basal transcription and impair glucose responsiveness of the promoter. These results therefore shed light on the mechanism by which the S14 protein, whose concentration rapidly rises after glucose intake, contributes to the full activity of the L-PK promoter.

Spot 14 protein interacts and co-operates with chicken ovalbumin upstream promoter-transcription factor 1 in the transcription of the L-type pyruvate kinase gene through a specificity protein 1 (Sp1) binding site

In hepatocytes, the amount of the Spot 14 (S14) protein is closely related to the full expression of enzymes involved in the glycolytic and lipogenic pathways. In the present study we address the role played by this protein in the control of transcription of the L-type pyruvate kinase (L-PK) gene in primary hepatocytes. We show that human S14, which by itself does not bind to the L-PK promoter, physically interacts with the human chicken ovalbumin upstream promoter-transcription factor 1 (COUP-TF1) and induces the switch of this factor from a repressor to an activator. However, the enhancing activity of S14 and COUP-TF1 depends on the presence of a proximal GC-rich box (the L0 element) that specifically binds nuclear proteins from the livers of rats fed a glucose-rich diet. Moreover, the L0 element, which strongly binds dephosphorylated specificity protein 1 (Sp1), loses all affinity when this factor is phosphorylated by cAMP-dependent protein kinase. Mutations that affect binding of Sp1 and nuclear proteins to the L0 box also decrease basal transcription and impair glucose responsiveness of the promoter. These results therefore shed light on the mechanism by which the S14 protein, whose concentration rapidly rises after glucose intake, contributes to the full activity of the L-PK promoter.

Splanchnic and systemic hemodynamic effects of sustained euglycemic hyperinsulinemia in rats.

Insulin, in addition to its metabolic function, was found to induce skeletal muscle vasodilatation after acute administration. The vasoactive effects of sustained euglycemic hyperinsulinemia, especially in the splanchnic circulation, are less well known. The aim of this study was to evaluate the systemic and splanchnic hemodynamic effects of sustained euglycemic hyperinsulinemia. Hyperinsulinemia was induced by a sustained-release insulin implant in the scurf area of male rats (release rate -1 U/day). Beginning on the 3rd day, the study group was fed a glucose-rich diet. Hemodynamic studies were performed on the 5th day using the radioactive microsphere technique. Serum insulin was measured by radioimmunoassay. At the time of the hemodynamic measurements, plasma insulin level was higher in the insulin-treated (n=8) compared to control rats (n=8) (23.6 +/- 4.7 vs. 13.2+/-3.9 microu/mL, respectively; p<0.001). Plasma glucose level of the two groups was similar (5.43 +/- 1.07 vs. 5.83 +/- 1.44 mmol/L, respectively). Abdominal skeletal muscle blood flow was higher in the insulin-treated group (0.11 +/- 0.05 vs. 0.05 +/- 0.04 mL x min(-1) x g(-1), respectively; p<0.02). No significant changes were observed in cardiac output and renal blood flow. In the splanchnic circulation: stomach, pancreatic, intestinal, splenic, hepatic arterial and total hepatic blood flow were also not significantly different. In summary, short-term, sustained euglycemic hyperinsulinemia in rats increased blood flow to skeletal muscle but had no hemodynamic effects on cardiac output or splanchnic circulation.

A glucose-rich diet shortens longevity of mice

High plasma levels of glucose and insulin over long time periods play an important role in the genesis of diabetic complications. There is evidence that the long term consumption of glucose-rich diet by rats is detrimental to insulin sensitivity. We investigated the effect of a glucose-rich diet on longevity of 70 female mice which were compared to 70 mice on a control diet. The average age of death of the control group was 568 ± 139 days compared to 511 ± 170 for the glucose group and the seven oldest mice of the control group died at age 890 ± 52 days, while the seven oldest mice of the glucose group died at 833 ± 49 days. These differences are statistically significant ( P ≤ 0.05). Our work shows that a life-long intake of a diet with 20% of total energy derived from glucose leads to a significant reduction of the average and maximal life-span in female mice and thus, supports previous observations of detrimental effects of high glucose intake over long periods.

Dietary and Hormonal Regulation of Aldolase B Gene Transcription in Rat Liver

In the liver of the fasted rat, the aldolase B (AldB) mRNA level decreased to about half of that of the control rat. When the control rat was refed the glucose-rich diet, the AldB mRNA level increased about six to seven times more than in the fasted rat. This increase was shown as the activation of the AldB gene transcription by a nuclear run-on assay. To understand the causal factor(s) for this activation, the relationship between the AldB mRNA level in the liver and the plasma concentrations of hormones, which are known as major regulators of carbohydrate metabolism during fasting and refeeding, was investigated. The plasma insulin level in the rat which was refed the glucose-rich diet increased in parallel to AldB mRNA level, while the plasma glucagon level decreased reciprocally to it. The relationship of the plasma corticosterone level to the AldB mRNA level was not obvious. To directly confirm the effects of these hormones on AldB gene transcription in the liver, the responses of AldB gene in the primary cultured hepatocytes to these hormones were examined. Insulin and dexamethasone were effective to activate AldB gene, while glucagon and thyroxine were suppressive. Thyroxine did not extinguish the effects of insulin and dexamethasone, but glucagon canceled them. Thus, it is probable that in vivo these hormones synergistically regulate the AldB gene transcription. In vitro transcription analysis of two AldB promoter constructs suggested that the proximal half of the AldB promoter (up to -92 bp from the transcription start site) is, at least in part, involved for this induction, and the distal half which contains liver-specific elements (-93 to -202 bp) is not involved. The possible explanation for the dietary regulation of aldolase B gene transcription in the liver is discussed.

The effects of ethinylestradiol, a glucose diet and streptozotocin induced diabetes mellitus on gallstone formation and biliary lipid composition in the hamster

Possible risk factors for gallstone formation were examined and the concentrations of biliary lipids and each bile acid in the hepatic and gallbladder bile of hamsters were quantified. Forty female golden Syrian hamsters were divided into 4 groups according to diet; Group I, given control chow, Group II, given an ethinylestradiol and cholesterol supplemented diet, Group III, given a glucose rich diet without induced diabetes mellitus, and Group IV, given a glucose rich diet with diabetes mellitus induced by streptozotocin injection. The formation of cholesterol crystals but not gallstones was induced in Group II associated with a significantly decreased total bile acid concentration in the gallbladder bile but not in the hepatic bile. The formation of cholesterol gallstones and crystals with significantly higher concentrations of cholesterol and phospholipid was observed in Group III, while neither the formation of gallstones nor lithogenicity was enhanced by diabetes mellitus. However, a quite different lithogenicity was evident between the hepatic and gallbladder bile of the Group IV animals. These results suggest that neither the consumption of oral contraceptives nor diabetes mellitus induces gallstone formation, but that these factors can be responsible for dysfunction of the gallbladder.

Lack of dietary dependence of liver adenylate kinase levels

FEBS LettersVolume 93, Issue 2 p. 228-230 Full-length articleFree Access Lack of dietary dependence of liver adenylate kinase levels María Rosa De Sagarra, María Rosa De Sagarra Instituto de Enzimología del CSIC, Facultad de Medicina de la Universidad Autónoma, Madrid, SpainSearch for more papers by this author María Rosa De Sagarra, María Rosa De Sagarra Instituto de Enzimología del CSIC, Facultad de Medicina de la Universidad Autónoma, Madrid, SpainSearch for more papers by this author First published: September 15, 1978 https://doi.org/10.1016/0014-5793(78)81109-0Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume93, Issue2September 15, 1978Pages 228-230 ReferencesRelatedInformation

On lysosomal fragility and induction of liver hexose-monophosphate dehydrogenases in the fasted-refed rat

Young adult male rats were fasted for 3 days, then fed a glucose-rich diet, ad libitum. At the end of the fasting period, the specific activity of liver glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase was decreased to 60% of control (nonfasted) levels. After 24 to 72 h of refeeding, the specific activity of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase increased seven- and twofold, respectively. During the fasting period, the liver lysosome fragility increased, as judged by increased release of bound acid phosphatase and β- N-acetylglucosammidase activity during standard homogenization. Three hours after feeding a carbohydrate-rich diet, a further increase in liver lysosomal fragility was observed that returned to control values prior to the induction of the dehydrogenases. Similarly, the susceptibility of liver lysosomes from fasted rats to increased fragility by the intraperitoneal injection of glucose or galactose was also observed. Prior starvation was not a requisite for labilization of lysosomal membranes by injected glucose, but induction of the pentose phosphate shunt dehydrogenase was not observed. In a group of 6-week old male rats fed a commercial pellet diet throughout, the injection of insulin caused no change in liver lysosomal fragility, though hypoglycemia resulted. Similar animals made diabetic by treatment with Streptozotocin and diabetic rats given insulin, showed no change in liver lysosmal fragility based on the percentage of free to total activities of β- N-acetylglucosaminidase, β-glucuronidase, β-galactosidase, and Cathespin D. However, when adult female rats were fasted for 24 h, then injected with sufficient insulin to produce hypoglycemia, liver lysosomal fragility, based on the release of β- N-acetylglucosaminidase during homogenization, increased nearly threefold. These studies demonstrate that stimulated lysosomal fragility can be initiated by refeeding fasted animals a carbohydrate-rich diet, by intraperitoneal injections of fasted rats with glucose or galactose, or by administering insulin alone to fasted rats. However, hyperglycemia induced by diabetogenic doses of Streptozotocin, or hypoglycemia induced in well-fed animals by insulin injection failed to elicit an enhanced liver lysosomal fragility. Whether induction of the enzymes of lipogenesis by rat liver is dependent upon a prior lysosomal membrane labilization remains to be determined.