Effects of fructose on hepatic glucose metabolism in humans

2000 ◽  
Vol 279 (4) ◽  
pp. E907-E911 ◽  
Author(s):  
Mirjam Dirlewanger ◽  
Philippe Schneiter ◽  
Eric Jéquier ◽  
Luc Tappy
Keyword(s):  
Glycogen Synthesis ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Hepatic Glycogen ◽  
Healthy Humans ◽  
Hepatic Glucose Metabolism ◽  
Insulin Requirements ◽  
Hepatic Glucose ◽  
Total Glucose ◽  
Glucose Output

Hepatic and extrahepatic insulin sensitivity was assessed in six healthy humans from the insulin infusion required to maintain an 8 mmol/l glucose concentration during hyperglycemic pancreatic clamp with or without infusion of 16.7 μmol · kg−1 · min−1fructose. Glucose rate of disappearance (GRd), net endogenous glucose production (NEGP), total glucose output (TGO), and glucose cycling (GC) were measured with [6,6-2H2]- and [2-2H1]glucose. Hepatic glycogen synthesis was estimated from uridine diphosphoglucose (UDPG) kinetics as assessed with [1-13C]galactose and acetaminophen. Fructose infusion increased insulin requirements 2.3-fold to maintain blood glucose. Fructose infusion doubled UDPG turnover, but there was no effect on TGO, GC, NEGP, or GRd under hyperglycemic pancreatic clamp protocol conditions. When insulin concentrations were matched during a second hyperglycemic pancreatic clamp protocol, fructose administration was associated with an 11.1 μmol · kg−1 · min−1increase in TGO, a 7.8 μmol · kg−1 · min−1increase in NEGP, a 2.2 μmol · kg−1 · min−1increase in GC, and a 7.2 μmol · kg−1 · min−1decrease in GRd ( P < 0.05). These results indicate that fructose infusion induces hepatic and extrahepatic insulin resistance in humans.

scholarly journals Arrestin domain-containing 3 (Arrdc3) modulates insulin action and glucose metabolism in liver

2020 ◽  
Vol 117 (12) ◽  
pp. 6733-6740 ◽  
Author(s):  
Thiago M. Batista ◽  
Sezin Dagdeviren ◽  
Shannon H. Carroll ◽  
Weikang Cai ◽  
Veronika Y. Melnik ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Insulin Action ◽  
Hepatic Glucose Production ◽  
Glycogen Synthesis ◽  
Glucose Production ◽  
Hepatic Glycogen ◽  
Glycogen Accumulation ◽  
Hepatic Glucose ◽  
Glucose Output

Insulin action in the liver is critical for glucose homeostasis through regulation of glycogen synthesis and glucose output. Arrestin domain-containing 3 (Arrdc3) is a member of the α-arrestin family previously linked to human obesity. Here, we show thatArrdc3is differentially regulated by insulin in vivo in mice undergoing euglycemic-hyperinsulinemic clamps, being highly up-regulated in liver and down-regulated in muscle and fat. Mice with liver-specific knockout (KO) of the insulin receptor (IR) have a 50% reduction inArrdc3messenger RNA, while, conversely, mice with liver-specific KO ofArrdc3(L-Arrdc3KO) have increased IR protein in plasma membrane. This leads to increased hepatic insulin sensitivity with increased phosphorylation of FOXO1, reduced expression of PEPCK, and increased glucokinase expression resulting in reduced hepatic glucose production and increased hepatic glycogen accumulation. These effects are due to interaction of ARRDC3 with IR resulting in phosphorylation of ARRDC3 on a conserved tyrosine (Y382) in the carboxyl-terminal domain. Thus,Arrdc3is an insulin target gene, and ARRDC3 protein directly interacts with IR to serve as a feedback regulator of insulin action in control of liver metabolism.

Effects of dexamethasone on hepatic glucose production and fructose metabolism in healthy humans

1997 ◽  
Vol 273 (2) ◽  
pp. E315-E320 ◽  
Author(s):  
P. Tounian ◽  
P. Schneiter ◽  
S. Henry ◽  
J. Delarue ◽  
L. Tappy
Keyword(s):  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Healthy Men ◽  
Fructose Metabolism ◽  
Healthy Humans ◽  
Hepatic Glucose ◽  
Endogenous Glucose ◽  
Total Glucose ◽  
Administration Rate

This study was designed to determine whether glucocorticoids alter autoregulation of glucose production and fructose metabolism. Two protocols with either dexamethasone (DEX) or placebo (Placebo) were performed in six healthy men during hourly ingestion of[13C]fructose (1.33 mmol.kg-1.h-1) for 3 h. In both protocols, endogenous glucose production (EGP) increased by 8 (Placebo) and 7% (DEX) after fructose, whereas gluconeogenesis from fructose represented 82 (Placebo) and 72% (DEX) of EGP. Fructose oxidation measured from breath 13CO2 was similar in both protocols [9.3 +/- 0.7 (Placebo) and 9.6 +/- 0.5 mumol.kg-1.min-1 (DEX)]. Nonoxidative carbohydrate disposal, calculated as fructose administration rate minus net carbohydrate oxidation rate after fructose ingestion measured by indirect calorimetry, was also similar in both protocols [5.8 +/- 0.8 (Placebo) and 5.9 +/- 2.0 mumol.kg-1.min-1 (DEX)]. We concluded that dexamethasone 1) does not alter the autoregulatory process that prevents a fructose-induced increase in gluconeogenesis from increasing total glucose production and 2) does not affect oxidative and nonoxidative pathways of fructose. This indicates that the insulin-regulated enzymes involved in these pathways are not affected in a major way by dexamethasone.

scholarly journals Is Insulin Action in the Brain Relevant in Regulating Blood Glucose in Humans?

2015 ◽  
Vol 100 (7) ◽  
pp. 2525-2531 ◽  
Author(s):  
Satya Dash ◽  
Changting Xiao ◽  
Cecilia Morgantini ◽  
Khajag Koulajian ◽  
Gary F. Lewis
Keyword(s):  
Plasma Glucose ◽  
Insulin Action ◽  
Hepatic Glucose Production ◽  
Glycogen Synthesis ◽  
Physiological Role ◽  
Glucose Production ◽  
Insulin Concentration ◽  
Hepatic Glycogen ◽  
Hepatic Glucose ◽  
Glucose Output

Purpose: In addition to its direct action on the liver to lower hepatic glucose production, insulin action in the central nervous system (CNS) also lowers hepatic glucose production in rodents after 4 hours. Although CNS insulin action (CNSIA) modulates hepatic glycogen synthesis in dogs, it has no net effect on hepatic glucose output over a 4-hour period. The role of CNSIA in regulating plasma glucose has recently been examined in humans and is the focus of this review. Methods and Results: Intransal insulin (INI) administration increases CNS insulin concentration. Hence, INI can address whether CNSIA regulates plasma glucose concentration in humans. We and three other groups have sought to answer this question, with differing conclusions. Here we will review the critical aspects of each study, including its design, which may explain these discordant conclusions. Conclusions: The early glucose-lowering effect of INI is likely due to spillover of insulin into the systemic circulation. In the presence of simultaneous portal and CNS hyperinsulinemia, portal insulin action is dominant. INI administration does lower plasma glucose independent of peripheral insulin concentration (between ∼3 and 6 h after administration), suggesting that CNSIA may play a role in glucose homeostasis in the late postprandial period when its action is likely greatest and portal insulin concentration is at baseline. The potential physiological role and purpose of this pathway are discussed in this review. Because the effects of INI are attenuated in patients with type 2 diabetes and obesity, this is unlikely to be of therapeutic utility.

Effects of infused fructose on endogenous glucose production, gluconeogenesis, and glycogen metabolism

1994 ◽  
Vol 267 (5) ◽  
pp. E710-E717 ◽  
Author(s):  
P. Tounian ◽  
P. Schneiter ◽  
S. Henry ◽  
E. Jequier ◽  
L. Tappy
Keyword(s):  
Control Experiment ◽  
Glycogen Synthesis ◽  
Glucose Production ◽  
Glycogen Metabolism ◽  
Endogenous Glucose Production ◽  
Hepatic Glucose Output ◽  
Hepatic Glucose ◽  
Endogenous Glucose ◽  
Glycogen Deposition ◽  
Glucose Output

To determine the mechanisms that prevent an increase in gluconeogenesis from increasing hepatic glucose output, six healthy women were infused with [1-13C]fructose (22 mumol.kg-1.min-1), somatostatin, insulin, and glucagon. In control experiment, non-13C-enriched fructose was infused at the same rate without somatostatin, and [U-13C]glucose was infused to measure specifically plasma glucose oxidation. Endogenous glucose production (EGP, [6,6-2H]glucose), net carbohydrate oxidation (CHOox, indirect calorimetry), and fructose oxidation (13CO2) were measured. EGP rate did not increase after fructose infusion with (13.1 +/- 1.2 vs. 12.9 +/- 0.3 mumol.kg-1.min-1) and without (10.3 +/- 0.5 vs. 9.7 +/- 0.5 mumol.kg-1.min-1) somatostatin, despite the fact that gluconeogenesis increased. Nonoxidative fructose disposal, corresponding mainly to glycogen synthesis, was threefold net glycogen deposition, the latter calculated as fructose infusion minus CHOox (14.8 +/- 1.1 and 4.3 +/- 2.0 mumol.kg-1.min-1). It is concluded that 1) the mechanism by which EGP remains constant when gluconeogenesis from fructose increases is independent of changes in insulin and 2) simultaneous breakdown and synthesis of glycogen occurred during fructose infusion.

Dexamethasone increases glucose cycling, but not glucose production, in healthy subjects

1990 ◽  
Vol 259 (5) ◽  
pp. E626-E632 ◽  
Author(s):  
A. Wajngot ◽  
A. Khan ◽  
A. Giacca ◽  
M. Vranic ◽  
S. Efendic
Keyword(s):  
Healthy Subjects ◽  
Glucose Production ◽  
Glucose Infusion ◽  
Metabolic Clearance ◽  
Hepatic Glucose Metabolism ◽  
Oral Dexamethasone ◽  
Hepatic Glucose ◽  
Early Effects ◽  
Total Glucose ◽  
Glucose Output

We established that measurement of glucose fluxes through glucose-6-phosphatase (G-6-Pase; hepatic total glucose output, HTGO), glucose cycling (GC), and glucose production (HGP), reveals early diabetogenic changes in liver metabolism. To elucidate the mechanism of the diabetogenic effect of glucocorticoids, we treated eight healthy subjects with oral dexamethasone (DEX; 15 mg over 48 h) and measured HTGO with [2-3H]glucose and HGP with [6-3H]glucose postabsorptively and during a 2-h glucose infusion (11.1 mumol.kg-1.min-1). [2-3H]- minus [6-3H]glucose equals GC. DEX significantly increased plasma glucose, insulin, C peptide, and HTGO, while HGP was unchanged. In controls and DEX, glucose infusion suppressed HTGO (82 vs. 78%) and HGP (87 vs. 91%). DEX increased GC postabsorptively (three-fold) P less than 0.005 and during glucose infusion (P less than 0.05) but decreased metabolic clearance and glucose uptake (Rd), which eventually normalized, however. Because DEX increased HTGO (G-6-Pase) and not HGP (glycogenolysis + gluconeogenesis), we assume that DEX increases HTGO and GC in humans by activating G-6-Pase directly, rather than by expanding the glucose 6-phosphate pool. Hyperglycemia caused by peripheral effects of DEX can also contribute to an increase in GC by activating glucokinase. Therefore, measurement of glucose fluxes through G-6-Pase and GC revealed significant early effects of DEX on hepatic glucose metabolism, which are not yet reflected in HGP.

scholarly journals The impact of obesity, sex, and diet on hepatic glucose production in cats

2009 ◽  
Vol 296 (4) ◽  
pp. R936-R943 ◽  
Author(s):  
Saskia Kley ◽  
Margarethe Hoenig ◽  
John Glushka ◽  
Eunsook S. Jin ◽  
Shawn C. Burgess ◽  
...  
Keyword(s):  
Phosphoenolpyruvate Carboxykinase ◽  
Citrate Synthase ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Hepatic Glucose Metabolism ◽  
Peripheral Insulin Resistance ◽  
Pyruvate Cycling ◽  
Hepatic Glucose ◽  
The Impact

Obesity is a risk factor for type 2 diabetes in cats. The risk of developing diabetes is severalfold greater for male cats than for females, even after having been neutered early in life. The purpose of this study was to investigate the role of different metabolic pathways in the regulation of endogenous glucose production (EGP) during the fasted state considering these risk factors. A triple tracer protocol using 2H2O, [U-13C3]propionate, and [3,4-13C2]glucose was applied in overnight-fasted cats (12 lean and 12 obese; equal sex distribution) fed three different diets. Compared with lean cats, obese cats had higher insulin ( P < 0.001) but similar blood glucose concentrations. EGP was lower in obese cats ( P < 0.001) due to lower glycogenolysis and gluconeogenesis (GNG; P < 0.03). Insulin, body mass index, and girth correlated negatively with EGP ( P < 0.003). Female obese cats had ∼1.5 times higher fluxes through phosphoenolpyruvate carboxykinase ( P < 0.02) and citrate synthase ( P < 0.05) than male obese cats. However, GNG was not higher because pyruvate cycling was increased 1.5-fold ( P < 0.03). These results support the notion that fasted obese cats have lower hepatic EGP compared with lean cats and are still capable of maintaining fasting euglycemia, despite the well-documented existence of peripheral insulin resistance in obese cats. Our data further suggest that sex-related differences exist in the regulation of hepatic glucose metabolism in obese cats, suggesting that pyruvate cycling acts as a controlling mechanism to modulate EGP. Increased pyruvate cycling could therefore be an important factor in modulating the diabetes risk in female cats.

scholarly journals Inhibition of glycogenolysis enhances gluconeogenic precursor uptake by the liver of conscious dogs

1997 ◽  
Vol 273 (5) ◽  
pp. E868-E879 ◽  
Author(s):  
Masakazu Shiota ◽  
Patricia A. Jackson ◽  
Hilmar Bischoff ◽  
Michael McCaleb ◽  
Melanie Scott ◽  
...  
Keyword(s):  
Glycogen Synthesis ◽  
Control Period ◽  
Glucose Production ◽  
Hepatic Uptake ◽  
Endogenous Glucose Production ◽  
Conscious Dogs ◽  
Intragastric Administration ◽  
Endogenous Insulin ◽  
Glucose Output ◽  
Gluconeogenic Substrates

We investigated the effect of inhibiting glycogenolysis on gluconeogenesis in 18-h-fasted conscious dogs with the use of intragastric administration of BAY R 3401, a glycogen phosphorylase inhibitor. Isotopic ([3-3H]glucose and [U-14C]alanine) and arteriovenous difference methods were used to assess glucose metabolism. Each study consisted of a 100-min equilibration, a 40-min control, and two 90-min test periods. Endogenous insulin and glucagon secretions were inhibited with somatostatin (0.8 μg ⋅ kg−1 ⋅ min−1), and the two hormones were replaced intraportally (insulin: 0.25 mU ⋅ kg−1 ⋅ min−1; glucagon: 0.6 ng ⋅ kg−1 ⋅ min−1). Drug (10 mg/kg) or placebo was given after the control period. Insulin and glucagon were kept at basal levels in the first test period, after which glucagon infusion was increased to 2.4 ng ⋅ kg−1 ⋅ min−1; BAY R 3401 decreased tracer-determined endogenous glucose production [rate of glucose production (Ra): 14 ± 1 to 7 ± 1 μmol ⋅ kg−1 ⋅ min−1] and net hepatic glucose output (11 ± 1 to 3 ± 2 μmol ⋅ kg−1 ⋅ min−1) during test 1. It increased the net hepatic uptake of gluconeogenic substrates from 9.0 ± 2.0 to 11.6 ± 0.6 μmol ⋅ kg−1 ⋅ min−1. Basal glycogenolysis was decreased by drug (9.1 ± 0.7 to 1.5 ± 0.2 μmol glucosyl U ⋅ kg−1 ⋅ min−1). Placebo had no effect on Ra or the uptake of gluconeogenic precursors by the liver. The rise in glucagon increased Ra by 22 ± 3 and by 8 ± 2 μmol ⋅ kg−1 ⋅ min−1(at 10 min) in placebo and drug, respectively. The rise in glucagon caused little change in the net hepatic uptake (μmol ⋅ kg−1 ⋅ min−1) of gluconeogenic substrates in placebo (8.2 ± 0.6 to 9.0 ± 1.0) but increased it markedly (11.6 ± 0.6 to 15.4 ± 1.0) in drug. Glucagon increased glycogenolysis by 22.1 ± 2.5 and by 7.8 ± 1.6 μmol ⋅ kg−1 ⋅ min−1in placebo and drug, respectively. The amount of glycogen (μmol glucosyl U/kg) synthesized from gluconeogenic carbon was four times higher in drug (48.6 ± 9.7) than in placebo (11.3 ± 1.7). We conclude that BAY R 3401 caused a marked reduction in basal and glucagon-stimulated glycogenolysis. As a result of these changes, there was an increase in the net hepatic uptake of gluconeogenic precursors and in glycogen synthesis.

Involvement of the vagus nerves in the regulation of basal hepatic glucose production in conscious dogs

2002 ◽  
Vol 283 (5) ◽  
pp. E958-E964 ◽  
Author(s):  
Sylvain Cardin ◽  
Konstantin Walmsley ◽  
Doss W. Neal ◽  
Phillip E. Williams ◽  
Alan D. Cherrington
Keyword(s):  
Hepatic Glucose Production ◽  
Control Period ◽  
Glucose Production ◽  
Heart Rate Change ◽  
Vagus Nerves ◽  
Hepatic Glucose Metabolism ◽  
Vagal Blockade ◽  
Hepatic Glucose ◽  
Cooling Coils ◽  
Glucose Output

We determined if blocking transmission in the fibers of the vagus nerves would affect basal hepatic glucose metabolism in the 18-h-fasted conscious dog. A pancreatic clamp (somatostatin, basal portal insulin, and glucagon) was employed. A 40-min control period was followed by a 90-min test period. In one group, stainless steel cooling coils (Sham, n = 5) were perfused with a 37°C solution, while in the other (Cool, n = 6), the coils were perfused with −20°C solution. Vagal blockade was verified by heart rate change (80 ± 9 to 84 ± 14 beats/min in Sham; 98 ± 12 to 193 ± 22 beats/min in Cool). The arterial glucose level was kept euglycemic by glucose infusion. No change in tracer-determined glucose production occurred in Sham, whereas in Cool it dropped significantly (2.4 ± 0.4 to 1.9 ± 0.4 mg · kg−1· min−1). Net hepatic glucose output did not change in Sham but decreased from 1.9 ± 0.3 to 1.3 ± 0.3 mg · kg−1· min−1in the Cool group. Hepatic gluconeogenesis did not change in either group. These data suggest that vagal blockade acutely modulates hepatic glucose production by inhibiting glycogenolysis.

scholarly journals Unlike mice, dogs exhibit effective glucoregulation during low-dose portal and peripheral glucose infusion

2004 ◽  
Vol 286 (2) ◽  
pp. E226-E233 ◽  
Author(s):  
Mary Courtney Moore ◽  
Sylvain Cardin ◽  
Dale S. Edgerton ◽  
Ben Farmer ◽  
Doss W. Neal ◽  
...  
Keyword(s):  
Low Dose ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Hepatic Glucose Output ◽  
Arterial Blood ◽  
Hepatic Glucose ◽  
Arterial Blood Glucose ◽  
Hepatic Portal ◽  
Glucose Output ◽  
Arteriovenous Difference

Portal infusion of glucose in the mouse at a rate equivalent to basal endogenous glucose production causes hypoglycemia, whereas peripheral infusion at the same rate causes significant hyperglycemia. We used tracer and arteriovenous difference techniques in conscious 42-h-fasted dogs to determine their response to the same treatments. The studies consisted of three periods: equilibration (100 min), basal (40 min), and experimental (180 min), during which glucose was infused at 13.7 μmol· kg–1·min–1 into a peripheral vein (PE, n = 5) or the hepatic portal (PO, n = 5) vein. Arterial blood glucose increased ∼0.8 mmol/l in both groups. Arterial and hepatic sinusoidal insulin concentrations were not significantly different between groups. PE exhibited an increase in nonhepatic glucose uptake (non-HGU; Δ8.6 ± 1.2 μmol·kg–1·min–1) within 30 min, whereas PO showed a slight suppression (Δ–3.7 ± 3.1 μmol·kg–1·min–1). PO shifted from net hepatic glucose output (NHGO) to uptake (NHGU; 2.5 ± 2.8 μmol·kg–1·min–1) within 30 min, but PE still exhibited NHGO (6.0 ± 1.9 μmol·kg–1·min–1) at that time and did not initiate NHGU until after 90 min. Glucose rates of appearance and disappearance did not differ between groups. The response to the two infusion routes was markedly different. Peripheral infusion caused a rapid enhancement of non-HGU, whereas portal delivery quickly activated NHGU. As a result, both groups maintained near-euglycemia. The dog glucoregulates more rigorously than the mouse in response to both portal and peripheral glucose delivery.

scholarly journals Autoregulation of hepatic glucose production

1998 ◽  
pp. 240-248 ◽  
Author(s):  
MC Moore ◽  
CC Connolly ◽  
AD Cherrington
Keyword(s):  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Hepatic Glycogen ◽  
Neural Pathways ◽  
Hepatic Glucose Output ◽  
Counterregulatory Hormones ◽  
Hepatic Glucose ◽  
Glucose Output

In vitro evidence indicates that the liver responds directly to changes in circulating glucose concentrations with reciprocal changes in glucose production and that this autoregulation plays a role in maintenance of normoglycemia. Under in vivo conditions it is difficult to separate the effects of glucose on neural regulation mediated by the central nervous system from its direct effect on the liver. Nevertheless, it is clear that nonhormonal mechanisms can cause significant changes in net hepatic glucose balance. In response to hyperglycemia, net hepatic glucose output can be decreased by as much as 60-90% by nonhormonal mechanisms. Under conditions in which hepatic glycogen stores are high (i.e. the overnight-fasted state), a decrease in the glycogenolytic rate and an increase in the rate of glucose cycling within the liver appear to be the explanation for the decrease in hepatic glucose output seen in response to hyperglycemia. During more prolonged fasting, when glycogen levels are reduced, a decrease in gluconeogenesis may occur as a part of the nonhormonal response to hyperglycemia. A substantial role for hepatic autoregulation in the response to insulin-induced hypoglycemia is most clearly evident in severe hypoglycemia (< or = 2.8 mmol/l). The nonhormonal response to hypoglycemia apparently involves enhancement of both gluconeogenesis and glycogenolysis and is capable of supplying enough glucose to meet at least half of the requirement of the brain. The nonhormonal response can include neural signaling, as well as autoregulation. However, even in the absence of the ability to secrete counterregulatory hormones (glucocorticoids, catecholamines, and glucagon), dogs with denervated livers (to interrupt neural pathways between the liver and brain) were able to respond to hypoglycemia with increases in net hepatic glucose output. Thus, even though the endocrine system provides the primary response to changes in glycemia, autoregulation plays an important adjunctive role.

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