Effect of cold exposure on plasma glucose and acetate turnover rates in sheep

2014 ◽  
Vol 54 (10) ◽  
pp. 1728 ◽  
Author(s):  
M. Al-Mamun ◽  
Y. Sako ◽  
H. Sano
Keyword(s):  
Plasma Concentration ◽  
Cold Exposure ◽  
Plasma Glucose ◽  
Turnover Rate ◽  
Isotopic Dilution ◽  
Glucose Turnover ◽  
Acetate Metabolism ◽  
Turnover Rates ◽  
Water Access ◽  
Esterified Fatty Acids

Isotopic dilution methodology of [U-13C]glucose and [1-13C]Na-acetate were performed simultaneously as primed continuous infusions to determine plasma glucose and acetate metabolism in sheep during thermoneutral (TN) and cold exposure (CE, 2−4°C). The experiment was performed using crossbred (Corriedale × Suffolk) sheep (n = 5; 3 male and 2 female; ~2 years old, 38 ± 2.5 kg of initial bodyweight). The animals were offered mixed hay of orchardgrass and reed canarygrass (40 : 60) 62 g/kg0.75/day with ad libitum water access. Concentration of plasma glucose was determined enzymatically using the glucose oxidase method. Plasma concentration of non-esterified fatty acids (NEFA) and glucose were higher (P = 0.01 and P = 0.05 respectively) during CE than TN. Plasma concentration and the turnover rate of acetate were numerically higher (P = 0.09 and P = 0.25 respectively) during CE than during TN. Plasma glucose turnover rate was higher (P = 0.02) during CE than TN. The present findings suggested that plasma acetate turnover rate tended to be elevated during CE, with further more extensive studies required to clarify the significance.

Glucose metabolism in thyroidectomized and normal dogs during rest and acute cold exposure

1975 ◽  
Vol 38 (2) ◽  
pp. 236-240 ◽  
Author(s):  
P. Paul ◽  
M. Donohue ◽  
W. L. Holmes
Keyword(s):  
Energy Expenditure ◽  
Glucose Level ◽  
Cold Exposure ◽  
Plasma Glucose ◽  
Turnover Rate ◽  
Control Period ◽  
Glucose Turnover ◽  
Glucose Levels ◽  
Acute Cold Exposure ◽  
Lower Glucose

Uniformly labeled (14C)glucose was infused iv at a constant rate into unanesthetized surgically thyroidectomized (THY) and normal dogs during the basal state at 22 degrees C and during cold exposure at 4–5 degrees C. 02 uptake, CO2 output, and plasma glucose levels were determined; from these rates of glucose turnover and oxidation were calculated. Comparison of THY with normal dogs shows that at a mean plasma glucose level of 103 mg/100 ml, a significantly lower glucose turnover rate was observed in THY dogs on the basis of a kg body weight, body surface area (m-2), but not per cal BMR. The same percentage of glucose turnover was immediately oxidized in THY and normal dogs, accounting for 16 and 15% of the total caloric expenditure, respectively. Acute cold exposure increased energy expenditure in both THY and normal dogs without a change in glucose level or turnover rate. However, the percentage of glucose turnover which was immediately oxidized as well as the amount of glucose oxidized increased significantly and proportionally to the increase in energy expenditure so that the percent of calories derived from plasma glucose oxidation remained the same as that observed during the control period.

The effects of methylprednisolone and diabetes on the turnover of alanine and on the transfer of carbon atoms from alanine to pyruvate and glucose in dogs

1980 ◽  
Vol 58 (7) ◽  
pp. 787-796 ◽  
Author(s):  
G. Hetenyi Jr. ◽  
B. Pagurek ◽  
Elizabeth A. Dittmar ◽  
Catherine Ferrarotto
Keyword(s):  
Plasma Level ◽  
Plasma Glucose ◽  
Turnover Rate ◽  
Glucose Turnover ◽  
Direct Proportion ◽  
Carbon Transfer ◽  
Tracer Methods ◽  
Pancreatectomized Dogs

The turnover rate of glucose, the irreversible disposal rate of alanine, and the transfer of carbon atoms from alanine to glucose were studied with the help of tracer methods in normal, methylprednisolone (MP) treated and pancreatectomized dogs. The incorporation of carbon from alanine into pyruvate was also followed. In comparison with normal dogs, in MP-treated dogs the plasma level of alanine and pyruvate were elevated by a factor of about 3 whereas the level of plasma glucose was increased by 10%. Both the turnover rate of glucose and the irreversible disposal rate of alanine were significantly higher. In pancreatectomized dogs plasma alanine and pyruvate levels were not different from normal. There was no increase in the irreversible disposal rate of alanine. Glucose turnover was about twice as much as in normals. The transfer of C atoms from alanine to glucose was increased in both MP-treated and pancreatectomized dogs. The increase was in direct proportion to the increase in the irreversible disposal rate of alanine in MP-treated dogs whereas in pancreatectomized dogs it was due to an increased fraction of the irreversible disposal rate of alanine being converted to circulating glucose. Thus two different mechanisms are responsible for the increased carbon transfer and hence presumably gluconeogenesis in MP-treated and in pancreatectomized animals. The role of insulin as the determinant of the preferred route to increase gluconeogenesis is discussed.

Mammalian metabolite flux rates in a teleost: lactate and glucose turnover in tuna

1986 ◽  
Vol 250 (3) ◽  
pp. R452-R458 ◽  
Author(s):  
J. M. Weber ◽  
R. W. Brill ◽  
P. W. Hochachka
Keyword(s):  
Blood Lactate ◽  
Turnover Rate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Lactate Clearance ◽  
Glucose Turnover ◽  
Skipjack Tuna ◽  
Turnover Rates ◽  
Total Blood ◽  
Lactate Turnover

Lactate and glucose turnover rates were measured by bolus injection of [U-14C]lactate and [6-3H]glucose in cannulated lightly anesthetized skipjack tuna, Katsuwonus pelamis. Our goals were to find out whether the high rates of lactate clearance reported during recovery from burst swimming in tuna could be accounted for by high blood lactate fluxes; to extend the observed correlation between lactate turnover and lactate concentration in mammals to a nonmammalian system, and to assess the importance of lactate and glucose as metabolic fuels in tuna and to compare their flux rates with values reported for mammals. Measured lactate turnover rates ranged from 112 to 431 mumol X min-1 X kg-1 and were correlated with blood lactate concentration. Glucose turnover rate averaged 15.3 mumol X min-1 X kg-1. When correcting for body mass and temperature, skipjack tuna has at least as high or even higher lactate turnover rates than those recorded for mammals. Tuna glucose turnover rate is similar to that of mammals but much higher than levels found in other teleosts. Even the highest lactate turnover rate measured in tuna cannot fully account for the rate of blood lactate clearance observed during recovery, suggesting that some of the lactate produced in skeletal muscle must be metabolized in situ. After injection of [U-14C]lactate, less than 5% of the total blood activity was recovered in glucose, suggesting that the Cori cycle is not an important pathway of lactate metabolism in tuna.

Steady state glucose kinetics and their relation to plasma glucose concentration in the premature and full term neonatal piglet

1981 ◽  
Vol 59 (10) ◽  
pp. 1069-1072 ◽  
Author(s):  
P. A. Flecknell ◽  
R. Wootton ◽  
Muriel John ◽  
J. P. Royston
Keyword(s):  
Steady State ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Turnover Rate ◽  
Full Term ◽  
Plasma Glucose Concentration ◽  
Human Infant ◽  
Glucose Turnover ◽  
Glucose Kinetics ◽  
Neonatal Piglet

Steady state glucose kinetics were measured in 19 premature and 16 full-term piglets. Bodyweight, plasma glucose concentration, total body glucose turnover rate, and glucose pool size were not significantly different between the two groups. This suggests that the premature piglet is capable of maintaining glucose homeostasis during the first 24 h of life. Although there appeared to be a correlation between glucose turnover and plasma glucose concentration, analysis of covariance showed that it was spurious, suggesting that glucose utilization proceeds independently of the glucose concentration in plasma.Glucose turnover rate in the premature piglet is closely comparable with that reported in the premature human infant. These findings encourage the use of the neonatal piglet as an animal model for the study of the problems of the neonatal human.

Insulin resistance, but normal basal rates of glucose production in patients with newly diagnosed mild diabetes mellitus

1991 ◽  
Vol 124 (6) ◽  
pp. 637-645 ◽  
Author(s):  
Ole Hother-Nielsen ◽  
Henning Beck-Nielsen
Keyword(s):  
Diabetes Mellitus ◽  
Plasma Glucose ◽  
Glucose Utilization ◽  
Ketone Bodies ◽  
Glucose Production ◽  
Glucose Turnover ◽  
Diabetic Patients ◽  
Newly Diagnosed ◽  
Turnover Rates ◽  
Mild Diabetes

Abstract. Fasting hyperglycemia in Type II (non-insulin-dependent) diabetes has been suggested to be due to hepatic overproduction of glucose and reduced glucose clearance. We studied 22 patients (10 lean and 12 obese) with newly diagnosed mild diabetes mellitus (fasting plasma glucose <15 mmol/l, urine ketone bodies <1 mmol/l), and two age- and weight-matched groups of non-diabetic control subjects. Glucose turnover rates and sensitivity to insulin were determined using adjusted primed-continuous [3-3H]glucose infusion and the hyperinsulinemic euglycemic clamp technique. Insulin-stimulated glucose utilization was reduced in both diabetic groups (lean patients: 313±35 vs 531±22 mg·m−2·min−1, p<0.01;obesepatients:311±28vs453±26mg·m−2·min−1, p<0.01). Basal plasma glucose concentrations decreased 0.43±0.05 mmol/l per h (p<0.01). Glucose production rates were smaller than glucose utilization rates (lean patients: 87±3 vs 94±3 mg·m−2·min−1, p<0.01; obese patients: 79±5 vs 88±5 mg·m−2 ·min−1, p<0.01), were not correlated to basal glucose or insulin concentrations, and were not different from normal (lean controls: 87±4 mg·−2·min−1; obese controls: 80±5 mg·m−2·min−1). These results suggest that the basal state in the diabetic patients is a compensated condition where glucose turnover rates are maintained near normal despite defects in insulin sensitivity.

Metabolic interrelations of glucose and lactate in unanesthetized normal and diabetic dogs

1970 ◽  
Vol 48 (2) ◽  
pp. 115-122 ◽  
Author(s):  
N. Forbath ◽  
G. Hetenyi Jr.
Keyword(s):  
Plasma Glucose ◽  
Turnover Rate ◽  
Recycling Rate ◽  
Glucose Turnover ◽  
Absolute Rate ◽  
Glucose Load ◽  
Plasma Lactate ◽  
Glucose Carbon ◽  
Diabetic Dogs ◽  
Pancreatectomized Dogs

Uniformly labelled 14C-glucose infusions were given to normal and pancreatectomized dogs. Plasma glucose and lactate specific activities were measured by appropriate methods. In normal dogs 14–28% of plasma lactate was found to originate from circulating glucose, and in diabetic dogs 11–18%. This fraction was markedly increased in normal but not significantly so in diabetic dogs during a 2-h infusion of a 6.7–11 mg/kg min glucose load. Uniformly labelled 14C-L(+)-lactate and glucose-6-3H were infused simultaneously for 5 h in normal and pancreatectomized dogs. The glucose turnover rate and incorporation of lactate carbon into glucose were calculated. Of the utilized lactate carbon, 41–49% was incorporated into plasma glucose. The recycling rate of glucose carbon via lactate was estimated to be 3–8% of the glucose turnover rate in the normal dog in the postabsorptive state. The absolute rate of gluconeogenesis from lactate was found to be increased in diabetes.

scholarly journals Glucose metabolism in vivo in fed and 48 h starved goats during pregnacy and lactation

1982 ◽  
Vol 47 (1) ◽  
pp. 87-94 ◽  
Author(s):  
N. Chaiyabutr ◽  
Anne Faulkner ◽  
M. Peaker
Keyword(s):  
Plasma Concentration ◽  
Glucose Metabolism ◽  
Continuous Infusion ◽  
Plasma Glucose ◽  
Glucose Turnover ◽  
Pregnancy And Lactation ◽  
Glucose Synthesis

1. Glucose turnover (i.e. glucose entry and utilization rates) in fed and 48 h starved goats during pregnancy and lactation was determined using a continuous infusion of [U-14C]- and [3-3H]glucose.2. Glucose synthesis and utilization increased during pregnancy and lactation in fed but not in starved goats.3. Recycling of giucosc-C was approximately 10% in fed animals and 15–20% in starved animals and was unaffected by the stage of pregnancy or lactation.4. Plasma glucose concentrations were maintained during pregnancy and lactation in fed goats but decreased during 48 h starvation in pregnant goats. Little change was seen in the plasma concentration of lipids and their metabolites during pregnancy and lactation in fed goats, but increases were observed after 48 h starvation.5. The control of glucose metabolism in ruminants during pregnancy and lactation is discussed.

Insulin resistance is associated with high sodium-lithium countertransport in essential hypertension

1991 ◽  
Vol 261 (6) ◽  
pp. E684-E691 ◽  
Author(s):  
A. Doria ◽  
P. Fioretto ◽  
A. Avogaro ◽  
A. Carraro ◽  
A. Morocutti ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Essential Hypertension ◽  
Plasma Glucose ◽  
Lactate Concentration ◽  
Isotopic Dilution ◽  
Glucose Turnover ◽  
Oral Glucose ◽  
Euglycemic Hyperinsulinemic Clamp ◽  
Hypertensive Patients ◽  
Insulin Levels

The nature of the association between essential hypertension and insulin resistance remains unknown. We measured plasma glucose and insulin levels after an oral glucose tolerance test (OGTT), as well as insulin sensitivity (using a euglycemic hyperinsulinemic clamp), glucose turnover (Rd; using [6,6-2H2]- and [3-3H]glucose isotopic dilution), and forearm net balance of glucose (using arterial-venous difference) in 22 hypertensive patients with high (H2) red blood cell (RBC) sodium-lithium countertransport (Na(+)-Li+ CT; greater than 0.41 mmol.l RBC-1.h-1), 21 hypertensive patients with normal (H1) Na(+)-Li+ CT, and 22 normotensive controls (C). After OGTT, H2 patients had higher plasma glucose and insulin levels than H1 and C. During euglycemic hyperinsulinemia (approximately 100 microU/ml) Rd was lower in H2 [21.7 +/- 1.4 (SE) mumol.kg-1.min-1] than in H1 (44.3 +/- 2.9; P less than 0.01) and C (48.1 +/- 3.0; P less than 0.01), and an inverse correlation was found between rates of Na(+)-Li+ CT and Rd in H1 and H2 (rs = -0.76; P less than 0.01). Forearm glucose uptake was 40-50% lower in H2 compared with H1 and C (P less than 0.01). Lactate concentration increased more in C (from 511 +/- 24 to 1,207 +/- 69 microM) and in H1 (from 564 +/- 40 to 1,122 +/- 99) than in H2 (from 581 +/- 42 to 950 +/- 102, P less than 0.05 vs. both). Forearm blood flow increased more in C (31%, P less than 0.05) and H1 (22%, P less than 0.05) than in H2 (12%).(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma glucose turnover during cold stress in humans

1995 ◽  
Vol 78 (4) ◽  
pp. 1296-1302 ◽  
Author(s):  
A. L. Vallerand ◽  
J. Zamecnik ◽  
I. Jacobs
Keyword(s):  
Cold Stress ◽  
Cold Exposure ◽  
Plasma Glucose ◽  
Glucose Oxidation ◽  
Carbohydrate Oxidation ◽  
Whole Body ◽  
Gas Chromatography Mass Spectrometry ◽  
Glucose Turnover ◽  
Lactate Oxidation ◽  
The Difference

To clarify the source of increased carbohydrate oxidation during cold stress, six males rested for 3 h at 29 and 10 degrees C dressed only in shorts. After priming the blood glucose and bicarbonate pools, [U-13C6]glucose was infused for 3 h in each condition to determine the plasma glucose rate of appearance (Ra) or turnover under relative steady-state conditions. Plasma enrichment (mol %excess) was determined by selective ion-monitoring gas chromatography-mass spectrometry. Cold exposure decreased rectal temperature and mean skin temperature and increased heat debt, metabolic rate, and whole body lipid and carbohydrate oxidation (CHOox) compared with the same subjects at thermal neutrality (P < 0.05). Cold exposure significantly increased Ra from 13.18 +/- 0.70 to 16.22 +/- 0.43 mumol.kg-1.min-1 (P < 0.05). Plasma glucose clearance was elevated commensurately by the cold (from 2.68 +/- 0.16 to 3.55 +/- 0.14 ml.kg-1.min-1; P < 0.05). If we assume that Ra is completely oxidized (thus equivalent to maximum rates of plasma glucose oxidation) [J. A. Romijn, E. F. Coyle, L. S. Sidossis, A. Gastaldelli, J. F. Horowitz, E. Endert, and R. R. Wolfe. Am. J. Physiol. 265 (Endocrinol. Metab. 28): E380-E391, 1993], the minimum rates of glycogen and lactate oxidation in the cold would be the difference between CHOox and glucose oxidation (approximately 14.0 +/- 3.0 mumol.kg-1.min-1). Therefore, under the present laboratory conditions, 54% of CHOox would be fueled by plasma glucose oxidation, whereas the remaining 46% would be derived from the combination of glycogen and lactate oxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Gluconeogenesis from glycine and serine in fasted normal and diabetic rats

1988 ◽  
Vol 253 (1) ◽  
pp. 27-32 ◽  
Author(s):  
G Hetenyi ◽  
P J Anderson ◽  
M Raman ◽  
C Ferrarotto
Keyword(s):  
Amino Acids ◽  
Plasma Concentration ◽  
Blood Plasma ◽  
Plasma Glucose ◽  
De Novo ◽  
Specific Radioactivity ◽  
Diabetic Rats ◽  
Glucose Turnover ◽  
Direct Proportion ◽  
Glucose Carbon

1. Non-anaesthetized normal and diabetic rats were fasted for 1 day, and [U-14C]glycine, or [U-14C]serine, or [U-14C]- plus [3-3H]-glucose was injected intra-arterially. The rates of synthesis de novo/irreversible disposal for glycine, serine and glucose, as well as the contribution of carbon atoms by the amino acids to plasma glucose, were calculated from the integrals of the specific-radioactivity-versus-time curves in plasma. 2. The concentrations of both glycine and serine in blood plasma were lower in diabetic than in fasted normal animals. 3. The rates of synthesis de novo/irreversible disposal of both amino acids tended to be lower in diabetic animals, but the decrease was statistically significant only for serine (14.3 compared with 10.5 mumol/min per kg). 4. Of the carbon atoms of plasma glucose, 2.9% arose from glycine in both fasted normal and diabetic rats, whereas 4.46% of glucose carbon originated from serine in fasted normal and 6.77% in diabetic rats. 5. As judged by their specific radioactivities, plasma serine and glycine exchange carbon atoms rapidly and extensively. 6. It was concluded that the turnover of glycine remains essentially unchanged, whereas that of serine is decreased in diabetic as compared with fasted normal rats. The plasma concentration of both amino acids was lower in diabetic rats. Both glycine and serine are glucogenic. In diabetic rats the contribution of carbon atoms from glycine to glucose increases in direct proportion to the increased glucose turnover, whereas the contribution by serine becomes also proportionally higher.

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