scholarly journals Glucose metabolism in the superovulated rat ovary in vitro. Effects of luteinizing hormone and the role of glucose metabolism in steroidogenesis

1969 ◽  
Vol 112 (2) ◽  
pp. 243-254 ◽  
Author(s):  
A. P. F. Flint ◽  
R M Denton
Keyword(s):  
Carbon Dioxide ◽  
Glucose Metabolism ◽  
Luteinizing Hormone ◽  
Glucose Uptake ◽  
Hormone Treatment ◽  
Total Lipid Extract ◽  
Rat Ovary

1. Superovulated rat ovary slices from rats treated with 20μg. of luteininzing hormone/100g. body wt. 2hr. before death and from control animals have been incubated in vitro. Output of Δ4-3-oxo steroids (0·2μmole/g. wet wt./hr. in control tissue) was linear for 4hr., and was increased by approx. 70% in slices from luteinizing hormone-treated rats. Rate of oxygen consumption (90·0±4·6μmoles/g. wet wt./hr.) was linear for 3hr. and unaltered by luteinizing hormone treatment or addition of glucose (1mg./ml.) to the medium. 2. In slices from control animals, steady-state rate of glucose uptake was 78·0±2·9μg. atoms of carbon/g. wet wt./hr.; steady-state rates of lactate output, pyruvate output and incorporation of [U−14C]-glucose carbon atoms into carbon dioxide and total lipid extract were 60·7±0·9, 2·4±0·1, 18·0±1·1 and 0·7±0·1μg. atom of carbon/g. wet wt./hr. and accounted for 104·5±1·9% of the glucose uptake. In slices from luteinizing hormone-treated rats, glucose uptake and outputs of lactate, pyruvate and [14C]carbon dioxide were increased by approx. 25%, and 108·4±3·2% of the glucose uptake could be accounted for. 3. The total lipid extract was separated by thin-layer chromatography and saponification. Of the 14C incorporated into this fraction during incubation with [U−14C]glucose 97% was found in the fractions containing glyceride glycerol and less than 3% in the fractions containing sterols, steroids or fatty acids. Appreciable quantities of 14C were incorporated into these lipid fractions from [1−14C]acetate. 4. From a consideration of the tissue glycogen content, the specific activities of [14C]lactate and glucose 6-phosphate (C-1) derived from [1−14C]-, [6−14C]- and [U−14C]-glucose, and the ratio of [14C]carbon dioxide yields from [1−14C]glucose and [6−14C]glucose, it was concluded that there was no appreciable glycogenolysis or flow through the pentose phosphate cycle. 5. In ovary slices from both control and luteinizing hormone-treated animals, glucose in vitro raised the incorporation rate of 14C from [1−14C]acetate into sterols and steroids. Luteinizing hormone in vivo stimulated the incorporation rate in vitro but only in the presence of glucose. 6. In slices incubated in medium containing [3H]water, [14C]sorbitol and glucose (1mg./ml.), the total water space (865±7·1μl./g.) and the extracellular water space (581±22μl./g.) were unchanged by luteinizing hormone treatment in vivo but the glucose space was raised from 540±23·6μl./g. to 639±31·3μl./g. 7. Luteinizing hormone treatment was found to lower the tissue concentration of the hexose monophosphates and to increase the total activity of hexokinase, glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase and possibly of phosphofructokinase. 8. The kinetic properties of a partially purified preparation of phosphofructokinase were found to be qualitatively similar to those from other mammalian tissues. 9. The results are discussed with reference to both the role of glucose metabolism in steroidogenesis and the mechanism by which luteinizing hormone increases the rate of glucose uptake.

In vitro analysis of glucose metabolism and embryonic growth in postimplantation rat embryos

Development ◽  
1987 ◽  
Vol 100 (3) ◽  
pp. 431-439 ◽  
Author(s):  
S.K. Ellington
Keyword(s):  
Glucose Metabolism ◽  
Embryonic Development ◽  
Glucose Uptake ◽  
Glucose Concentration ◽  
Culture Media ◽  
Rat Embryos ◽  
Embryonic Growth ◽  
Stage Of Development

The glucose metabolism and embryonic development of rat embryos during organogenesis was studied using embryo culture. Glucose uptake and embryonic growth and differentiation of 10.5-day explants (embryos + membranes) were limited by the decreasing glucose concentration, but not the increasing concentration of metabolites, in the culture media during the second 24 h of a 48 h culture. No such limitations were found on the embryonic development of 9.5-day explants during a 48 h culture although glucose uptake was slightly reduced at very low concentrations of glucose. From the head-fold stage to the 25-somite stage of development, glucose uptake was characteristic of the stage of development of the embryo and not the time it had been in culture. Embryonic growth of 9.5-day explants was similar to that previously observed in vivo. Glucose uptake by 9.5-day explants was dependent on the surface area of the yolk sac and was independent of the glucose concentration in the culture media (within the range of 9.4 to 2.5 mM). The proportion of glucose converted to lactate was 100% during the first 42h of culture then fell to about 50% during the final 6h. The protein contents of both the extraembryonic membranes and the embryo were dependent on the glucose uptake.

Transgenic overexpression of intraislet ghrelin does not affect insulin secretion or glucose metabolism in vivo

2012 ◽  
Vol 302 (4) ◽  
pp. E403-E408 ◽  
Author(s):  
Mika Bando ◽  
Hiroshi Iwakura ◽  
Hiroyuki Ariyasu ◽  
Hiroshi Hosoda ◽  
Go Yamada ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Glucose Metabolism ◽  
Medium Chain Triglyceride ◽  
Physiological Role ◽  
Standard Diet ◽  
Entry Site ◽  
Insulin Secretion In Vivo

Whereas ghrelin is produced primarily in the stomach, a small amount of it is produced in pancreatic islets. Although exogenous administration of ghrelin suppresses insulin secretion in vitro or in vivo, the role of intraislet ghrelin in the regulation of insulin secretion in vivo remains unclear. To understand the physiological role of intraislet ghrelin in insulin secretion and glucose metabolism, we developed a transgenic (Tg) mouse model, rat insulin II promoter ghrelin-internal ribosomal entry site-ghrelin O-acyl transferase (RIP-GG) Tg mice, in which mouse ghrelin cDNA and ghrelin O-acyltransferase are overexpressed under the control of the rat insulin II promoter. Although pancreatic desacyl ghrelin levels were elevated in RIP-GG Tg mice, pancreatic ghrelin levels were not altered in animals on a standard diet. However, when Tg mice were fed a medium-chain triglyceride-rich diet (MCTD), pancreatic ghrelin levels were elevated to ∼16 times that seen in control animals. It seems likely that the gastric ghrelin cells possess specific machinery to provide the octanoyl acid necessary for ghrelin acylation but that this machinery is absent from pancreatic β-cells. Despite the overexpression of ghrelin, plasma ghrelin levels in the portal veins of RIP-GG Tg mice were unchanged from control levels. Glucose tolerance, insulin secretion, and islet architecture in RIP-GG Tg mice were not significantly different even when the mice were fed a MCTD. These results indicate that intraislet ghrelin does not play a major role in the regulation of insulin secretion in vivo.

scholarly journals Zinc Regulates Glucose Metabolism of the Spinal Cord and Neurons and Promotes Functional Recovery after Spinal Cord Injury through the AMPK Signaling Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-27
Author(s):  
Hengshuo Hu ◽  
Nan Xia ◽  
Jiaquan Lin ◽  
Daoyong Li ◽  
Chuanjie Zhang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Nervous System ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Functional Recovery ◽  
Glucose Metabolism Disorders ◽  
Cord Injury

Spinal cord injury (SCI) is a traumatic disease that can cause severe nervous system dysfunction. SCI often causes spinal cord mitochondrial dysfunction and produces glucose metabolism disorders, which affect neuronal survival. Zinc is an essential trace element in the human body and plays multiple roles in the nervous system. This experiment is intended to evaluate whether zinc can regulate the spinal cord and neuronal glucose metabolism and promote motor functional recovery after SCI. Then we explore its molecular mechanism. We evaluated the function of zinc from the aspects of glucose uptake and the protection of the mitochondria in vivo and in vitro. The results showed that zinc elevated the expression level of GLUT4 and promoted glucose uptake. Zinc enhanced the expression of proteins such as PGC-1α and NRF2, reduced oxidative stress, and promoted mitochondrial production. In addition, zinc decreased neuronal apoptosis and promoted the recovery of motor function in SCI mice. After administration of AMPK inhibitor, the therapeutic effect of zinc was reversed. Therefore, we concluded that zinc regulated the glucose metabolism of the spinal cord and neurons and promoted functional recovery after SCI through the AMPK pathway, which is expected to become a potential treatment strategy for SCI.

scholarly journals Functional properties of edible insects: a systematic review

2021 ◽  
pp. 1-54
Author(s):  
V. D’Antonio ◽  
N. Battista ◽  
G. Sacchetti ◽  
C. Di Mattia ◽  
M. Serafini
Keyword(s):  
Glucose Metabolism ◽  
Functional Role ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
Edible Insects ◽  
Cellular Models ◽  
Pubmed Database

Abstract Consumption of edible insects has been widely suggested as an environmentally sustainable substitute for meat to reduce GHG emissions. However, the novel research field for edible insects rely on the content of bioactive ingredients and on the ability to induce a functional effect in humans. The goal of this manuscript was to review the available body of evidence on the properties of edible insects in modulating oxidative and inflammatory stress, platelet aggregation, lipid and glucose metabolism and weight control. A search for literature investigating the functional role of edible insects was carried out in the PUBMED database using specific keywords. A total of 55 studies, meeting inclusion criteria after screening, were divided on the basis of the experimental approach: in vitro studies, cellular models/ex vivo studies or in vivo studies. In the majority of the studies, insects demonstrated the ability to reduce oxidative stress, modulate antioxidant status, restore the impaired activity of antioxidant enzymes and reduce markers of oxidative damage. Edible insects displayed anti-inflammatory activity reducing cytokines and modulating specific transcription factors. Results from animal studies suggest that edible insects can modulate lipid and glucose metabolism. The limited number of studies focused on the assessment of anticoagulation activity of edible insects make it difficult to draw conclusions. More evidence from dietary intervention studies in humans is needed to support the promising evidence from in vitro and animal models about the functional role of edible insects consumption.

scholarly journals Gout and pseudo-gout-related crystals promote GLUT1-mediated glycolysis that governs NLRP3 and interleukin-1β activation on macrophages

2020 ◽  
Vol 79 (11) ◽  
pp. 1506-1514
Author(s):  
Felix Renaudin ◽  
Lucie Orliaguet ◽  
Florence Castelli ◽  
François Fenaille ◽  
Aurelie Prignon ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Glucose Uptake ◽  
Aerobic Glycolysis ◽  
Metabolic Reprogramming ◽  
Metabolic Phenotype ◽  
Glucose Transporter 1 ◽  
Gout Flare

ObjectiveMacrophage activation by monosodium urate (MSU) and calcium pyrophosphate (CPP) crystals mediates an interleukin (IL)-1β-dependent inflammation during gout and pseudo-gout flare, respectively. Since metabolic reprogramming of macrophages goes along with inflammatory responses dependently on stimuli and tissue environment, we aimed to decipher the role of glycolysis and oxidative phosphorylation in the IL-1β-induced microcrystal response.MethodsBriefly, an in vitro study (metabolomics and real-time extracellular flux analysis) on MSU and CPP crystal-stimulated macrophages was performed to demonstrate the metabolic phenotype of macrophages. Then, the role of aerobic glycolysis in IL-1β production was evaluated, as well in vitro as in vivo using 18F-fluorodeoxyglucose positron emission tomography imaging and glucose uptake assay, and molecular approach of glucose transporter 1 (GLUT1) inhibition.ResultsWe observed that MSU and CPP crystals led to a metabolic rewiring toward the aerobic glycolysis pathway explained by an increase in GLUT1 plasma membrane expression and glucose uptake on macrophages. Also, neutrophils isolated from human synovial fluid during gout flare expressed GLUT1 at their plasma membrane more frequently than neutrophils isolated from bloodstream. Both glucose deprivation and treatment with either 2-deoxyglucose or GLUT1 inhibitor suppressed crystal-induced NLRP3 activation and IL-1β production, and microcrystal inflammation in vivo.ConclusionIn conclusion, we demonstrated that GLUT1-mediated glucose uptake is instrumental during the inflammatory IL-1β response induced by MSU and CPP crystals. These findings open new therapeutic paths to modulate crystal-related inflammation.

scholarly journals Role of nitric oxide in the control of luteinizing hormone-releasing hormone release in vivo and in vitro.

1993 ◽  
Vol 90 (21) ◽  
pp. 10130-10134 ◽  
Author(s):  
V. Rettori ◽  
N. Belova ◽  
W. L. Dees ◽  
C. L. Nyberg ◽  
M. Gimeno ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Luteinizing Hormone ◽  
Hormone Release ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone

scholarly journals TGF-βRII regulates glucose metabolism in oral cancer-associated fibroblasts via promoting PKM2 nuclear translocation

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Fanglong Wu ◽  
Shimeng Wang ◽  
Qingxiang Zeng ◽  
Junjiang Liu ◽  
Jin Yang ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Oral Cancer ◽  
Nuclear Translocation ◽  
Aerobic Glycolysis ◽  
Critical Role ◽  
Metabolic Reprogramming ◽  
Cancer Associated Fibroblasts

AbstractCancer-associated fibroblasts (CAFs) are highly heterogeneous and differentiated stromal cells that promote tumor progression via remodeling of extracellular matrix, maintenance of stemness, angiogenesis, and modulation of tumor metabolism. Aerobic glycolysis is characterized by an increased uptake of glucose for conversion into lactate under sufficient oxygen conditions, and this metabolic process occurs at the site of energy exchange between CAFs and cancer cells. As a hallmark of cancer, metabolic reprogramming of CAFs is defined as reverse Warburg effect (RWE), characterized by increased lactate, glutamine, and pyruvate, etc. derived from aerobic glycolysis. Given that the TGF-β signal cascade plays a critical role in RWE mainly through metabolic reprogramming related proteins including pyruvate kinase muscle isozyme 2 (PKM2), however, the role of nuclear PKM2 in modifying glycolysis remains largely unknown. In this study, using a series of in vitro and in vivo experiments, we provide evidence that TGF-βRII overexpression suppresses glucose metabolism in CAFs by attenuating PKM2 nuclear translocation, thereby inhibiting oral cancer tumor growth. This study highlights a novel pathway that explains the role of TGF-βRII in CAFs glucose metabolism and suggests that targeting TGF-βRII in CAFs might represent a therapeutic approach for oral cancer.

Insulin binding and action in adipocytes in vitro in relation to insulin action in vivo in young and middle-aged subjects

1986 ◽  
Vol 113 (1) ◽  
pp. 88-92 ◽  
Author(s):  
Hannele Yki-Jarvinen ◽  
Tuula Kiviluoto ◽  
Esko A. Nikkila
Keyword(s):  
Adipose Tissue ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Young Group ◽  
Middle Aged ◽  
Young Subjects ◽  
Aged Subjects

Abstract. The effect of age on glucose metabolism in vivo was compared to that found in adipocytes in vitro in young (n = 8, age 23 to 31 years) and middle-aged (n = 7, age 37 to 55 years) non-diabetic subjects. During the OGTT, the incremental glucose or insulin areas did not differ significantly between the groups. Fasting and 2 h plasma glucose (P < 0.01) and the 2 h plasma insulin (P < 0.05) levels were, however, slightly higher in the middle-aged than in the young group. During iv induced hyperinsulinaemia (~ 85 mU/l), rates of glucose uptake were comparable between the middle-aged (6.32 ± 0.94 mg/kg/min) and the young subjects (7.56 ± 0.78 mg/kg/min, P > 0.5). In fat cells, both basal and insulin stimulated rates of glucose transport were 35% lower (P < 0.05) in the middle-aged than in the young subjects. Basal and insulin stimulated rates of glucose oxidation and lipogenesis were both markedly lower (P <0.01) in the middle-aged than in the young group. The rates of glucose transport, oxidation and lipogenesis were inversely related to age, whereas none of these parameters was related to fat cell size. In conclusion, adipocyte glucose metabolism in middle-aged healthy subjects was markedly impaired. In contrast, rates of glucose uptake during iv hyperinsulinaemia and glucose responses during hyperinsulinaemia in the OGTT were comparable in young and middle-aged subjects. These results indicate first, that changes in adipose tissue glucose metabolism by aging do not parallel changes in whole body glucose metabolism and thus are specific for adipose tissue. Secondly, insulin-mediated glucose uptake is not reduced in middle-aged subjects. Thus, the small elevation in fasting and 2-h glucose levels may reflect a reduction in glucose uptake by non-insulin dependent pathways by aging.

Energetic dependence of NPY-induced LH secretion in a teleost fish (Dicentrarchus labrax)

1999 ◽  
Vol 277 (6) ◽  
pp. R1627-R1634 ◽  
Author(s):  
José Miguel Cerdá-Reverter ◽  
Lisa Ann Sorbera ◽  
Manuel Carrillo ◽  
Silvia Zanuy
Keyword(s):  
Glucose Metabolism ◽  
Luteinizing Hormone ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
Pituitary Cells ◽  
Lh Secretion ◽  
Dose Dependent Increase ◽  
Dose Dependent

The purpose of this work was to examine the role of energetic status in neuropeptide Y (NPY)-induced luteinizing hormone (LH) secretion and glucose metabolism in fish. Fasted juvenile sea bass ( Dicentrarchus labrax) were injected intraperitoneally with pig (p) NPY or pNPY + glucose, whereas fed animals were injected with pNPY alone and plasma glucose, insulin, and LH levels were examined. pNPY alone or in combination with glucose was found to induce a dose-dependent increase in LH secretion in fasted animals. Similar LH responses to pNPY were observed in vitro in dispersed pituitary cells isolated from fed and fasted animals incubated in L-15 and restricted media. Injection of pNPY + glucose in fasted animals resulted in depletion of glucose. Insulin plasma levels decreased in fasted animals coinjected with pNPY + glucose but remained stable when NPY was administrated alone to fed and fasted animals. Results suggest that 1) NPY-induced LH secretion in fish is dependent on energetic status and 2) NPY is capable of modifying glucose metabolism.

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