Paradoxical insulin-induced increase in gluconeogenesis in response to prolonged hypoglycemia in conscious dogs

1995 ◽  
Vol 268 (3) ◽  
pp. E521-E530 ◽  
Author(s):  
S. N. Davis ◽  
R. Dobbins ◽  
C. Tarumi ◽  
J. Jacobs ◽  
D. Neal ◽  
...  
Keyword(s):  
Insulin Infusion ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Conscious Dogs ◽  
High Dose ◽  
Insulin Levels ◽  
Arterial Blood ◽  
Hepatic Glucose ◽  
Dose Infusion ◽  
Arterial Insulin

The aim of this study was to determine the effects of differing insulin concentrations on the gluconeogenic response to equivalent prolonged hypoglycemia. Insulin was infused intraportally, for 3 h, into normal 18-h fasted conscious dogs at 2 (lower, n = 6) or 8 mU.kg-1.min-1 (high, n = 7) on separate occasions. This resulted in steady-state arterial insulin levels of 80 +/- 8 and 610 +/- 55 microU/ml, respectively. Glucose was infused during high dose to maintain the hypoglycemic plateau (50 +/- 1 mg/dl) equivalent to lower. Epinephrine (806 +/- 180 vs. 2,589 +/- 260 pg/ml), norepinephrine (303 +/- 55 vs. 535 +/- 60 pg/ml), cortisol (5.8 +/- 1.2 vs. 12.1 +/- 1.5 micrograms/dl), and pancreatic polypeptide (598 +/- 250 vs. 1,198 +/- 150 pg/ml) were all increased (P < 0.05) in the presence of high-dose insulin. Net hepatic glucose production increased significantly from 2.2 +/- 0.3 to 3.8 +/- 0.5 mg.kg-1.min-1 (P < 0.05) during high-dose infusion but remained at basal levels (2.3 +/- 0.4 mg.kg-1.min-1) during lower-dose insulin. During the 3rd h of hypoglycemia, gluconeogenesis accounted for between 42 and 100% of glucose production during high-dose infusion but only 22-52% during lower-dose insulin. Intrahepatic gluconeogenic efficiency, however, increased similarly during both protocols. Lipolysis, as indicated by arterial blood glycerol levels, increased by a greater amount during high- compared with lower-dose insulin infusion. Six hyperinsulinemic euglycemic control experiments (2 or 8 mU.kg-1.min-1, n = 3 in each) provided baseline data. Gluconeogenesis remained similar to basal levels, but lipolysis was significantly suppressed during both series of hyperinsulinemic euglycemic studies. In summary, these data suggest that 1) the important counterregulatory processes of gluconeogenesis and lipolysis can be significantly increased during prolonged hypoglycemia despite an eightfold increase in circulating insulin levels and 2) the amplified gluconeogenic rate present during the hypoglycemic high-dose insulin infusions was caused by enhanced substrate delivery to the liver rather than an increase in intrahepatic gluconeogenic efficiency.

Effects of differing insulin levels on response to equivalent hypoglycemia in conscious dogs

1992 ◽  
Vol 263 (4) ◽  
pp. E688-E695 ◽  
Author(s):  
S. N. Davis ◽  
R. Dobbins ◽  
C. Tarumi ◽  
C. Colburn ◽  
D. Neal ◽  
...  
Keyword(s):  
Plasma Glucose ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Conscious Dogs ◽  
High Dose ◽  
Insulin Levels ◽  
Glucose Levels ◽  
Hepatic Glucose ◽  
High Insulin ◽  
Arterial Insulin

The aim of this study was to determine if differing concentrations of insulin can modify the counterregulatory response to equivalent hypoglycemia. Insulin was infused intraportally into normal 18-h-fasted conscious dogs at 2 (low, n = 6) or 8 mU.kg-1.min-1 (high, n = 7) on separate occasions. This resulted in steady-state arterial insulin levels of 80 +/- 8 and 610 +/- 55 microU/ml, respectively. Glucose was infused during the high dose to maintain plasma glucose similar to low (50 +/- 1 mg/dl). Despite similar plasma glucose levels, epinephrine (2,589 +/- 260, 806 +/- 180 pg/ml), norepinephrine (535 +/- 60, 303 +/- 55 pg/ml), cortisol (12.1 +/- 1.5, 5.8 +/- 1.2 micrograms/dl), and pancreatic polypeptide (1,198 +/- 150, 598 +/- 250 pg/ml) were all increased in the presence of high-dose insulin (P < 0.05). Glucagon levels were similar during both insulin infusions. Hepatic glucose production, measured with [3-3H]-glucose, rose from 2.6 +/- 0.2 to 4.7 +/- 0.3 mg.kg-1.min-1 in response to high insulin (P < 0.01) but remained unchanged, 3.0 +/- 0.5 mg.kg-1.min-1, during low-dose infusions. Six hyperinsulinemic euglycemic control experiments (2 or 8 mU.kg-1.min-1, n = 3 in each) provided baseline data. By the final hour of the high-dose euglycemic clamps, cortisol (2.4 +/- 0.4 to 4.8 +/- 0.8 micrograms/dl) and norepinephrine (125 +/- 34 to 278 +/- 60 pg/ml) had increased (P < 0.05) compared with baseline. Plasma epinephrine levels remained unchanged during both series of euglycemic studies.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals The Irs1 Branch of the Insulin Signaling Cascade Plays a Dominant Role in Hepatic Nutrient Homeostasis

2009 ◽  
Vol 29 (18) ◽  
pp. 5070-5083 ◽  
Author(s):  
Shaodong Guo ◽  
Kyle D. Copps ◽  
Xiaocheng Dong ◽  
Sunmin Park ◽  
Zhiyong Cheng ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
High Fat Diet ◽  
Insulin Infusion ◽  
Dominant Role ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
High Fat ◽  
Lipogenic Genes ◽  
Hepatic Glucose ◽  
Nutrient Homeostasis

ABSTRACT We used a Cre-loxP approach to generate mice with varied expression of hepatic Irs1 and Irs2 to establish the contribution of each protein to hepatic nutrient homeostasis. While nutrient-sensitive transcripts were expressed nearly normally in liver lacking Irs2 (LKO2 mice), these transcripts were significantly dysregulated in liver lacking Irs1 (LKO1 mice) or Irs1 and Irs2 together (DKO mice). Similarly, a set of key gluconeogenic and lipogenic genes was regulated nearly normally by feeding in liver retaining a single Irs1 allele without Irs2 (DKO/1 mice) but was poorly regulated in liver retaining one Irs2 allele without Irs1 (DKO/2 mice). DKO/2 mice, but not DKO/1 mice, also showed impaired glucose tolerance and insulin sensitivity—though both Irs1 and Irs2 were required to suppress hepatic glucose production during hyperinsulinemic-euglycemic clamp. In contrast, either hepatic Irs1 or Irs2 mediated suppression of HGP by intracerebroventricular insulin infusion. After 12 weeks on a high-fat diet, postprandial tyrosine phosphorylation of Irs1 increased in livers of control and LKO2 mice, whereas tyrosine phosphorylation of Irs2 decreased in control and LKO1 mice. Moreover, LKO1 mice—but not LKO2 mice—that were fed a high-fat diet developed postprandial hyperglycemia. We conclude that Irs1 is the principal mediator of hepatic insulin action that maintains glucose homeostasis.

Effect of a selective rise in hepatic artery insulin on hepatic glucose production in the conscious dog

1999 ◽  
Vol 276 (4) ◽  
pp. E806-E813
Author(s):  
Dana K. Sindelar ◽  
Kayano Igawa ◽  
Chang A. Chu ◽  
Jim H. Balcom ◽  
Doss W. Neal ◽  
...  
Keyword(s):  
Portal Vein ◽  
Hepatic Artery ◽  
Insulin Infusion ◽  
Hepatic Glucose Production ◽  
Control Period ◽  
Glucose Production ◽  
Insulin Level ◽  
Hepatic Glucose ◽  
Glucose Output ◽  
Selective Increase

In the present study we compared the hepatic effects of a selective increase in hepatic sinusoidal insulin brought about by insulin infusion into the hepatic artery with those resulting from insulin infusion into the portal vein. A pancreatic clamp was used to control the endocrine pancreas in conscious overnight-fasted dogs. In the control period, insulin was infused via peripheral vein and the portal vein. After the 40-min basal period, there was a 180-min test period during which the peripheral insulin infusion was stopped and an additional 1.2 pmol ⋅ kg−1⋅ min−1of insulin was infused into the hepatic artery (HART, n = 5) or the portal vein (PORT, n = 5, data published previously). In the HART group, the calculated hepatic sinusoidal insulin level increased from 99 ± 20 (basal) to 165 ± 21 pmol/l (last 30 min). The calculated hepatic artery insulin concentration rose from 50 ± 8 (basal) to 289 ± 19 pmol/l (last 30 min). However, the overall arterial (50 ± 8 pmol/l) and portal vein insulin levels (118 ± 24 pmol/l) did not change over the course of the experiment. In the PORT group, the calculated hepatic sinusoidal insulin level increased from 94 ± 30 (basal) to 156 ± 33 pmol/l (last 30 min). The portal insulin rose from 108 ± 42 (basal) to 192 ± 42 pmol/l (last 30 min), whereas the overall arterial insulin (54 ± 6 pmol/l) was unaltered during the study. In both groups hepatic sinusoidal glucagon levels remained unchanged, and euglycemia was maintained by peripheral glucose infusion. In the HART group, net hepatic glucose output (NHGO) was suppressed from 9.6 ± 2.1 μmol ⋅ kg−1⋅ min−1(basal) to 4.6 ± 1.0 μmol ⋅ kg−1⋅ min−1(15 min) and eventually fell to 3.5 ± 0.8 μmol ⋅ kg−1⋅ min−1(last 30 min, P < 0.05). In the PORT group, NHGO dropped quickly ( P < 0.05) from 10.0 ± 0.9 (basal) to 7.8 ± 1.6 (15 min) and eventually reached 3.1 ± 1.1 μmol ⋅ kg−1⋅ min−1(last 30 min). Thus NHGO decreases in response to a selective increase in hepatic sinusoidal insulin, regardless of whether it comes about because of hyperinsulinemia in the hepatic artery or portal vein.

Nasal insulin administration does not affect hepatic glucose production at systemic fasting insulin levels

2019 ◽  
Vol 21 (4) ◽  
pp. 993-1000
Author(s):  
Peter Plomgaard ◽  
Jakob S. Hansen ◽  
Bodil Ingerslev ◽  
Jens O. Clemmesen ◽  
Niels H. Secher ◽  
...  
Keyword(s):  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Fasting Insulin ◽  
Insulin Administration ◽  
Insulin Levels ◽  
Hepatic Glucose

Interaction of free fatty acids and epinephrine in regulating hepatic glucose production in conscious dogs

2003 ◽  
Vol 284 (2) ◽  
pp. E291-E301 ◽  
Author(s):  
Chang An Chu ◽  
Pietro Galassetti ◽  
Kayano Igawa ◽  
Dana K. Sindelar ◽  
Doss W. Neal ◽  
...  
Keyword(s):  
Fatty Acids ◽  
High Glucose ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Conscious Dogs ◽  
Control Groups ◽  
Hepatic Glucose ◽  
Glycogenolytic Effect ◽  
Plasma Ffa ◽  
Arterial Plasma

To determine the effects of an increase in lipolysis on the glycogenolytic effect of epinephrine (EPI), the catecholamine was infused portally into 18-h-fasted conscious dogs maintained on a pancreatic clamp in the presence [portal (Po)-EPI+FFA, n = 6] and absence (Po-EPI+SAL, n = 6) of peripheral Intralipid infusion. Control groups with high glucose (70% increase) and free fatty acid (FFA; 200% increase; HG+FFA, n = 6) and high glucose alone (HG+SAL, n = 6) were also included. Hepatic sinusoidal EPI levels were elevated (Δ568 ± 77 and Δ527 ± 37 pg/ml, respectively) in Po-EPI+SAL and EPI+FFA but remained basal in HG+FFA and HG+SAL. Arterial plasma FFA increased from 613 ± 73 to 1,633 ± 101 and 746 ± 112 to 1,898 ± 237 μmol/l in Po-EPI+FFA and HG+FFA but did not change in EPI+SAL or HG+SAL. Net hepatic glycogenolysis increased from 1.5 ± 0.3 to 3.1 ± 0.4 mg · kg−1 · min−1( P < 0.05) by 30 min in response to portal EPI but did not rise (1.8 ± 0.2 to 2.1 ± 0.3 mg · kg−1 · min−1) in response to Po-EPI+FFA. Net hepatic glycogenolysis decreased from 1.7 ± 0.2 to 0.9 ± 0.2 and 1.6 ± 0.2 to 0.7 ± 0.2 mg · kg−1 · min−1by 30 min in HG+FFA and HG+SAL. Hepatic gluconeogenic flux to glucose 6-phosphate increased from 0.6 ± 0.1 to 1.2 ± 0.1 mg · kg−1 · min−1( P < 0.05; by 3 h) and 0.7 ± 0.1 to 1.6 ± 0.1 mg · kg−1 · min−1( P < 0.05; at 90 min) in HG+FFA and Po-EPI+FFA. The gluconeogenic parameters remained unchanged in the Po-EPI+SAL and HG+SAL groups. In conclusion, increased FFA markedly changed the mechanism by which EPI stimulated hepatic glucose production, suggesting that its overall lipolytic effect may be important in determining its effect on the liver.

scholarly journals Sleeve Gastrectomy Suppresses Hepatic Glucose Production and Increases Hepatic Insulin Clearance Independent of Weight-Loss

2021 ◽  
Author(s):  
Rachel Ben-Haroush Schyr ◽  
Abbas Al-Kurd ◽  
Botros Moalem ◽  
Anna Permyakova ◽  
Hadar Israeli ◽  
...  
Keyword(s):  
Weight Loss ◽  
Sleeve Gastrectomy ◽  
Hepatic Steatosis ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Insulin Clearance ◽  
Insulin Metabolism ◽  
Insulin Levels ◽  
Hepatic Glucose ◽  
Hepatic Insulin Clearance

Bariatric surgeries induce weight loss which is associated with an improvement in hepatic steatosis and reduction in hepatic glucose production. It is not clear whether these outcomes are entirely due to weight-loss, or whether the new anatomy imposed by the surgery contributes to the improvement in the metabolic function of the liver. We performed vertical sleeve gastrectomy (VSG) on obese mice provided with a high-fat high-sucrose diet, and compared them to diet and weight-matched sham-operated mice (WMS). 40 days after surgery, VSG-operated mice displayed lesser hepatic steatosis compared to WMS. By measuring the fasting glucose and insulin levels in the blood vessels feeding and draining the liver we showed directly that hepatic glucose production was suppressed after VSG. Insulin levels were elevated in the portal vein, and hepatic insulin clearance was elevated in VSG-operated mice. The hepatic expression of genes associated with insulin clearance was upregulated. We repeated the experiment in lean mice and observed that portal insulin and glucagon are elevated, but only insulin clearance is increased in VSG-operated mice. In conclusion, direct measurement of glucose and insulin in the blood entering and leaving the liver shows that VSG affects glucose and insulin metabolism through weight-loss and diet-independent mechanisms.

scholarly journals Sleeve Gastrectomy Suppresses Hepatic Glucose Production and Increases Hepatic Insulin Clearance Independent of Weight-Loss

2021 ◽  
Author(s):  
Rachel Ben-Haroush Schyr ◽  
Abbas Al-Kurd ◽  
Botros Moalem ◽  
Anna Permyakova ◽  
Hadar Israeli ◽  
...  
Keyword(s):  
Weight Loss ◽  
Sleeve Gastrectomy ◽  
Hepatic Steatosis ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Insulin Clearance ◽  
Insulin Metabolism ◽  
Insulin Levels ◽  
Hepatic Glucose ◽  
Hepatic Insulin Clearance

Bariatric surgeries induce weight loss which is associated with an improvement in hepatic steatosis and reduction in hepatic glucose production. It is not clear whether these outcomes are entirely due to weight-loss, or whether the new anatomy imposed by the surgery contributes to the improvement in the metabolic function of the liver. We performed vertical sleeve gastrectomy (VSG) on obese mice provided with a high-fat high-sucrose diet, and compared them to diet and weight-matched sham-operated mice (WMS). 40 days after surgery, VSG-operated mice displayed lesser hepatic steatosis compared to WMS. By measuring the fasting glucose and insulin levels in the blood vessels feeding and draining the liver we showed directly that hepatic glucose production was suppressed after VSG. Insulin levels were elevated in the portal vein, and hepatic insulin clearance was elevated in VSG-operated mice. The hepatic expression of genes associated with insulin clearance was upregulated. We repeated the experiment in lean mice and observed that portal insulin and glucagon are elevated, but only insulin clearance is increased in VSG-operated mice. In conclusion, direct measurement of glucose and insulin in the blood entering and leaving the liver shows that VSG affects glucose and insulin metabolism through weight-loss and diet-independent mechanisms.

Influence of somatostatin on glucagon- and epinephrine-stimulated hepatic glucose output in the dog.

1979 ◽  
Vol 236 (2) ◽  
pp. E113
Author(s):  
L Saccà ◽  
R Sherwin ◽  
P Felig
Keyword(s):  
Plasma Glucose ◽  
Glucose Production ◽  
Conscious Dogs ◽  
Insulin Deficiency ◽  
Hepatic Glucose Output ◽  
Glucose Kinetics ◽  
Insulin Levels ◽  
Hepatic Glucose ◽  
Glucose Output ◽  
Insulin Replacement

Glucose kinetics were measured using [3-3H]glucose in conscious dogs during the infusion of: 1) glucagon alone; 2) glucagon plus somatostatin with insulin replacement; 3) epinephrine alone; and 4) epinephrine plus somatostatin with insulin and glucagon replacement. Infusion of glucagon alone resulted in a 10-15 mg/dl rise in plasma glucose and a transient 45% rise in glucose production. When somatostatin and insulin were added, a four- to fivefold greater rise in plasma glucose and glucose production was observed. Glucagon levels were comparable to those achieved with infusion of glucagon alone, whereas peripheral insulin levels increased three- to fourfold above baseline, suggesting adequate replacement of preinfusion portal insulin levels. Infusion of epinephrine alone produced a 40% rise in plasma glucose and a 100% rise in glucose production. When somatostatin, insulin, and glucagon were added to epinephrine, the rise in glucose production was reduced in 65% despite replacement of glucagon levels and presumably mild portal insulin deficiency. These findings suggest that somatostatin: 1) potentiates the stimulatory effect of physiologic hyperglucagonemia on glucose production independent of insulin availability and 2) blunts the stimulatory effect of physiologic increments of epinephrine independent of glucagon availability.

Effect of loss of first-phase insulin secretion on hepatic glucose production and tissue glucose disposal in humans

1989 ◽  
Vol 257 (2) ◽  
pp. E241-E246 ◽  
Author(s):  
L. Luzi ◽  
R. A. DeFronzo
Keyword(s):  
Insulin Secretion ◽  
Insulin Infusion ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Second Phase ◽  
C Peptide ◽  
Hyperglycemic Clamp ◽  
Study Protocols ◽  
Hepatic Glucose ◽  
First Phase Insulin Secretion

To examine the importance of first-phase insulin secretion on total body glucose homeostasis, six normal subjects (age, 24 +/- 1 yr; ideal body wt, 100 +/- 1%) received three hyperglycemic (+75 mg/100 ml) clamp studies in combination with [3-3H]glucose: study I, 150 min hyperglycemic clamp; study II, hyperglycemic clamp plus somatostatin (6 micrograms/min) plus basal glucagon replacement (0.4 ng.kg-1.min-1) plus an insulin infusion designed to mimic only the second phase of insulin secretion; and study III, hyperglycemic clamp plus somatostatin plus basal glucagon plus an insulin infusion designed to mimic both the first and second phase of insulin secretion. Basal plasma C-peptide concentrations averaged 0.21 +/- 0.01 pmol/ml in the three study protocols. In study I the plasma C-peptide response demonstrated an early burst within the first 10 min followed by a gradually increasing phase of C-peptide secretion that lasted until the end of the study. In studies II and III plasma C-peptide declined within the first 10 min after somatostatin was started and averaged 0.06 +/- 0.01 and 0.05 +/- 0.01 pmol/min, respectively. Basal hepatic glucose production (2.3 +/- 0.2 mg.kg-1.min-1) was suppressed by 90% at 20 min and remained suppressed thereafter in studies I and III. In contrast, in study II hepatic glucose production was inhibited by only 50% (1.1 +/- 0.2 mg.kg-1.min-1) at 60 min (P less than 0.01 vs. studies I and III) and remained incompletely suppressed even after 150 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition by insulin of hepatic glucose production in the normal dog

1965 ◽  
Vol 208 (2) ◽  
pp. 301-306 ◽  
Author(s):  
R. Steele ◽  
J. S. Bishop ◽  
A. Dunn ◽  
N. Altszuler ◽  
I. Rathgeb ◽  
...  
Keyword(s):  
Production Rate ◽  
Insulin Infusion ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Glucose Release ◽  
Endogenous Insulin ◽  
Intravenous Insulin ◽  
Hepatic Glucose ◽  
Endogenous Glucose

Glucose-C14 was given intravenously in trace amount as an initial dose followed by continuous infusion to tag the circulating glucose of normal unanesthetized dogs in the post-absorptive state. The rate of dilution of this circulating tagged glucose by new (C12) glucose produced endogenously was measured. The release to the blood of such new glucose, presumably almost entirely from liver, was reduced by half during the 1st hr of intravenous insulin infusion at 0.1 U/kg per hr or more, provided that enough glucose was also infused to limit hypoglycemia. During the 2nd hr new glucose release was reduced by three-quarters or more. Insulin infusion at lower rates (02–.04 U/kg per hr), along with glucose, produced smaller effects. Glucose alone, infused intravenously in amounts sufficient to raise plasma glucose concentration, and hence presumed to enhance endogenous insulin secretion, reduced new glucose release by half during the 1st hr of infusion at one-half to one and one-half times the resting endogenous glucose production rate In the 2nd or 3rd hr, with glucose infusion increased to two to five times the resting endogenous glucose production rate, new glucose release was reduced by three-fourths or more.

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