Few are familiar with the gluconeogenesis that occurs in the intestine under fasting or the influence of insulin. Recently, however, studies that revealed the function of intestinal gluconeogenesis as a regulatory process for glucose homeostasis and appetite were described. The intestine produces about 25% of total endogenous glucose during fasting and regulates energy homeostasis through communication with the brain. Glucose produced via intestinal gluconeogenesis is delivered to portal vein where periportal neural system senses glucose and sends a signal to the brain to regulate appetite and glucose homeostasis. Moreover, studies uncovered that intestinal gluconeogenesis contributes to the rapid metabolic improvements induced by gastric bypass surgery.
Appetite ; Bariatric Surgery ; Brain ; Fasting ; Gastric Bypass ; Gluconeogenesis ; Glucose* ; Homeostasis ; Insulin ; Intestines* ; Metabolism* ; Portal Vein

Insulin resistance and diabetes combine to impair mitochondrial oxidative metabolism and cause lipid accumulation in non-adipose tissues such as skeletal muscles and the liver. The thyroid hormone stimulates thermogenesis, mitochondrial biogenesis, and various metabolisms, including gluconeogenesis and fatty-acid oxidation. Therefore, altered thyroid hormone action may induce the mitochondrial phenotype associated with insulin resistance. This review focuses on the correlation between thyroid hormone function and diabetes and the possible mechanisms associated with intracellular thyroid hormone dysfunction due to impaired metabolism.
Gluconeogenesis ; Insulin ; Insulin Resistance ; Liver ; Organelle Biogenesis ; Muscle, Skeletal ; Phenotype ; Thermogenesis ; Thyroid Gland

People whose diabetes is under good metabolic control should not experience more illness or infection than people without diabetes. However, when any illness occurs in someone with diabetes, the potential for hyperglycemia, hyperglycemia with ketosis, hyperglycemia with ketoacidosis, or hypoglycemia exists and requires education and treatment to prevent exacerbation or even possible death. In some parts of the world where access to medical care, insulin, or parenteral fluids is problematic, the added metabolic stress of an illness in someone with diabetes can be life threatening. Many illnesses are associated with higher levels of stress hormones which promote gluconeogenesis and insulin resistance. Education about the effects of concurrent illness ("sick days") is a critical component of diabetes management and must be adapted to the educational abilities and treatment possibilities of the particular situations in different parts of the world.
Diabetes Mellitus ; Gluconeogenesis ; Humans ; Hyperglycemia ; Hypoglycemia ; Insulin ; Insulin Resistance ; Ketosis ; Sick Leave ; Stress, Physiological

It is well known that the kidney is important for maintaining glucose homeostasis in vivo. However, the physiological role of the kidney in glucose metabolism is typically underestimated. Recently, a new class of anti-diabetic medications that affect the renal glucose regulatory mechanism was introduced into the market, sparking the interest of many researchers to better understand this mechanism. In this article, I briefly describe the role of the kidney in glucose metabolism and the changes of its function in patients with diabetes mellitus.
Diabetes Mellitus ; Diabetes Mellitus, Type 2 ; Gluconeogenesis ; Glucose* ; Homeostasis ; Humans ; Kidney* ; Metabolism*

As an important enzyme for gluconeogenesis, mitochondrial phosphoenolpyruvate carboxykinase (PCK2) has further complex functions beyond regulation of glucose metabolism. Here, we report that conditional knockout of Pck2 in osteoblasts results in a pathological phenotype manifested as craniofacial malformation, long bone loss, and marrow adipocyte accumulation. Ablation of Pck2 alters the metabolic pathways of developing bone, particularly fatty acid metabolism. However, metformin treatment can mitigate skeletal dysplasia of embryonic and postnatal heterozygous knockout mice, at least partly via the AMPK signaling pathway. Collectively, these data illustrate that PCK2 is pivotal for bone development and metabolic homeostasis, and suggest that regulation of metformin-mediated signaling could provide a novel and practical strategy for treating metabolic skeletal dysfunction.
Mice ; Animals ; Metformin/pharmacology* ; Phosphoenolpyruvate Carboxykinase (ATP)/metabolism* ; Gluconeogenesis/genetics* ; Mice, Knockout

Glucose homeostasis is tightly regulated to meet the energy requirements of the vital organs and maintain an individual's health. The liver has a major role in the control of glucose homeostasis by controlling various pathways of glucose metabolism, including glycogenesis, glycogenolysis, glycolysis and gluconeogenesis. Both the acute and chronic regulation of the enzymes involved in the pathways are required for the proper functioning of these complex interwoven systems. Allosteric control by various metabolic intermediates, as well as post-translational modifications of these metabolic enzymes constitute the acute control of these pathways, and the controlled expression of the genes encoding these enzymes is critical in mediating the longer-term regulation of these metabolic pathways. Notably, several key transcription factors are shown to be involved in the control of glucose metabolism including glycolysis and gluconeogenesis in the liver. In this review, we would like to illustrate the current understanding of glucose metabolism, with an emphasis on the transcription factors and their regulators that are involved in the chronic control of glucose homeostasis.
Gluconeogenesis ; Glucose* ; Glycogenolysis ; Glycolysis ; Homeostasis ; Liver ; Metabolic Networks and Pathways ; Metabolism* ; Negotiating ; Protein Processing, Post-Translational ; Transcription Factors

Alcohol influences glucose metabolism in both diabetic and non-diabetic individuals. Moderate alcohol consumption significantly decreases fasting glucose levels, but does not affect postprandial glucose levels. However, acute alcohol intake without food may provoke hypoglycemia. Moderate alcohol consumption may inhibit gluconeogenesis and enhance insulin sensitivity, but excessive alcohol intake (three or more drinks per day) may contribute to hyperglycemia. Daily alcohol intake in diabetics should be limited to a moderate amount (one drink per day or less for women and two drinks per day or less for men). Moderate alcohol intake may have cardiovascular benefits for patients with diabetes, but the trade-off between the cardiovascular benefits versus the potential risk of lower adherence associated with self-care behaviors should be considered.
Alcohol Drinking ; Blood Glucose ; Diabetes Mellitus ; Fasting ; Female ; Gluconeogenesis ; Glucose ; Humans ; Hyperglycemia ; Hypoglycemia ; Insulin Resistance ; Self Care

OBJECTIVETo investigate the expressions of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) in the liver of mice with hyperhomocysteinemia (HHcy) and explore the mechanism of gluconeogenesis induced by homocysteine.

METHODSFifty mice were randomly divided into normal control group (n=25) and HHcy group (n=25) and fed with normal food and food supplemented with 1.5% methionine, respectively. After 3 months of feeding, the fasting blood glucose and insulin levels were determined, and HOMA insulin resistance index (HOMA-IR) was calculated. The expressions of G6Pase and PEPCK in the liver of mice were detected using RT-PCR and Western blotting.

RESULTSThe fasting blood glucose and insulin levels and HOMA-IR were significantly higher in HHcy group than in the control group (P<0.05). RT-PCR and Western blotting showed that the hepatic expressions of G6Pase and PEPCK mRNA and proteins increased significantly in HHcy group compared with those in the control group (P<0.05).

CONCLUSIONHomocysteine promotes gluconeogenesis to enhance glucose output and contribute to the occurrence of insulin resistance.

Animals ; Gluconeogenesis ; Glucose-6-Phosphatase ; metabolism ; Homocysteine ; blood ; Hyperhomocysteinemia ; metabolism ; Insulin Resistance ; Liver ; metabolism ; Male ; Mice ; Mice, Inbred Strains ; Phosphoenolpyruvate Carboxykinase (ATP) ; metabolism

OBJECTIVESTo explore the effects of endotoxemia on gluconeogenesis in livers and kidneys during acute hepatic failure.

METHODTwenty-four healthy male SD rats were randomly divided into four groups (6 rats in each group) and all of them were injected intraperitoneally with solutions: group I with normal saline, group II with 400 mg/kg of D-galactosamine (D-GaLN), group III with 400 mg/kg of D-GaLN plus 50 microg/kg lipopolysaccharide(LPS), and group IV with 400 mg/kg of D-GaLN plus 500 microg/kg LPS. At 6 hours after the administration of different solutions intraperitoneally, blood samples were collected to examine blood urea nitrogen (BUN) and serum creatinine. Realtime PCR was used to study the expression of phosphoenolpyruvate carboxykinase (PEPCK) in the livers and kidneys.

RESULTSNo endotoxemia developed in group I or group II but it was evident in group III and group IV. The level of endotoxemia in group IV was higher than in group III (8.05+/-0.43, 3.50+/-2.25, P<0.05). After 6 hours of administration of LPS in group IV, hypoglycemia appeared, and blood glucose was normal in the other three groups. BUN and serum creatinine were all normal in the four groups, except that blood urea nitrogen was elevated in group IV. The mRNA of PEPCK in livers decreased gradually in all the four groups (2.54+/-1.32 vs 1.87+/-0.15 vs 0.91+/-0.13 vs 0.44+/-0.42, P<0.05). In the kidneys there was no change in the expression of PEPCK in group I and group II (0.75+/-0.03 and 0.77+/-0.04, P>0.05), but it increased in group III (0.75+/-0.03 vs 1.63+/-0.86, P<0.05), and decreased in group IV (0.75+/-0.03 vs 0.13+/-0.07, P<0.05).

CONCLUSIONDuring acute hepatic failure severe endotoxemia would damage the function of gluconeogenesis in livers and kidneys by inhibiting transcription of PEPCK and this can induce hypoglycemia.

Animals ; Endotoxemia ; metabolism ; Gluconeogenesis ; Kidney ; metabolism ; Liver ; metabolism ; Liver Failure, Acute ; metabolism ; Male ; Phosphoenolpyruvate Carboxykinase (GTP) ; metabolism ; Rats ; Rats, Sprague-Dawley

Glucose homeostasis is tightly controlled by the regulation of glucose production in the liver and glucose uptake into peripheral tissues, such as skeletal muscle and adipose tissue. Under prolonged fasting, hepatic gluconeogenesis is mainly responsible for glucose production in the liver, which is essential for tissues, organs, and cells, such as skeletal muscle, the brain, and red blood cells. Hepatic gluconeogenesis is controlled in part by the concerted actions of transcriptional regulators. Fasting signals are relayed by various intracellular enzymes, such as kinases, phosphatases, acetyltransferases, and deacetylases, which affect the transcriptional activity of transcription factors and transcriptional coactivators for gluconeogenic genes. Protein arginine methyltransferases (PRMTs) were recently added to the list of enzymes that are critical for regulating transcription in hepatic gluconeogenesis. In this review, we briefly discuss general aspects of PRMTs in the control of transcription. More specifically, we summarize the roles of four PRMTs: PRMT1, PRMT 4, PRMT 5, and PRMT 6, in the control of hepatic gluconeogenesis through specific regulation of FoxO1- and CREB-dependent transcriptional events.
Acetyltransferases ; Adipose Tissue ; Arginine* ; Brain ; Erythrocytes ; Fasting ; Gluconeogenesis ; Glucose* ; Homeostasis ; Liver ; Metabolism* ; Methyltransferases* ; Muscle, Skeletal ; Phosphoric Monoester Hydrolases ; Phosphotransferases ; Protein-Arginine N-Methyltransferases ; Transcription Factors