EFFECT OF FASTING ON PLASMA GLUCOSE KINETICS IN DOUBLE-MUSCLED CATTLE

1982 ◽  
Vol 62 (3) ◽  
pp. 955-958 ◽  
Author(s):  
R. A. STRATH ◽  
J. R. THOMPSON ◽  
R. J. CHRISTOPHERSON
Keyword(s):  
Key Words ◽  
Plasma Glucose ◽  
Pool Size ◽  
Irreversible Loss ◽  
Glucose Kinetics ◽  
Entry Rate

The effect of a 4-day fast on plasma glucose kinetics was determined with three 14-mo-old carrier bulls and three of their double-muscled (DM) half-siblings. Glucose entry rate and irreversible loss were less (P < 0.05) during fasting for both animal types. Glucose pool size was greater (P < 0.05) in carrier than in DM bulls. Key words: Plasma, glucose kinetics, double-muscled bulls

Effects of intraruminal infusions of urea, sucrose or urea plus sucrose on plasma urea and glucose kinetics in sheep fed chopped lucerne hay

1993 ◽  
Vol 121 (1) ◽  
pp. 125-130 ◽  
Author(s):  
Y. Obara ◽  
D. W. Dellow
Keyword(s):  
Plasma Glucose ◽  
Rumen Fluid ◽  
Glucose Production ◽  
Ammonia Concentration ◽  
Irreversible Loss ◽  
Glucose Kinetics ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Urea Kinetics ◽  
Plasma Urea Concentration

SUMMARYThe effect of rumen fermentation on the relationship between urea and glucose kinetics was examined in sheep fed chopped lucerne hay with intraruminal infusions of water, urea, sucrose, or urea plus sucrose at Palmerston North, New Zealand in 1986. Sheep were fed hourly and infused intraruminally with water (1200 m1/day), or a similar volume containing either urea alone (13·7g/day), sucrose alone (178·2 g/day) or urea (14·6 g/day) plus sucrose (175·0 g/day). The added sucrose resulted in a lower rumen ammonia concentration (P< 0·05), lower plasma urea concentration (P< 0·05) and reduced urinary urea excretion (P< 0·05). Urea recycled to the gut tended to increase with the sucrose, urea or sucrose plus urea treatments compared with the water treatment. The fermentation of sucrose in the rumen resulted in decreases in ruminal pH (P< 0·05) and in the ratio of acetate to propionate (A:P) (P< 0·05). The infusion of sucrose also increased the concentration of propionate in rumen fluid (P< 0·05), tended to increase the plasma glucose level and increased plasma glucose irreversible loss (P< 0·05). The infusion of urea resulted in an increase in the plasma urea level (P< 0·05), urea pool size (P< 0·05) and urea irreversible loss (P< 0·01). However, urea infusion did not affect glucose metabolism or volatile fatty acid (VFA) fermentation. The effects of sucrose infusion on glucose and urea kinetics were broadly similar when given alone or with urea, apart from changes in the urea degradation rate. It was concluded that the additional fermentative activity resulting from sucrose increased propionate production which, in turn, was available for glucose production, thus ‘sparing’ amino acids for tissue protein utilization and reducing urea excretion.

GLUCOSE AND ALANINE METABOLISM IN CHRONICALLY COLD-EXPOSED SHEEP

1990 ◽  
Vol 70 (2) ◽  
pp. 517-524 ◽  
Author(s):  
RICHARD J. EARLY ◽  
JAMES R. THOMPSON ◽  
ROBERT J. CHRISTOPHERSON
Keyword(s):  
Glucose Metabolism ◽  
Key Words ◽  
Cold Exposure ◽  
Plasma Glucose ◽  
Feed Intake ◽  
Pool Size ◽  
Per Se

Glucose and alanine metabolic interrelationships (measured with 3H-glucose and 14C-alanine) were examined in closely shorn wethers subjected to thermoneutral (TN) temperatures or chronic cold exposure (CE, < 21 d). Three treatments (n = 5–6 per treatment) were used: (1) fed to maintain weight at 18–20 °C (TN-Low); (2) fed to maintain weight at 0–4 °C (1.5 × TN-Low intake, CE-Hi); and (3) fed at CE-Hi intake at 18–20 °C (TN-Hi) to distinguish effects of the higher feed intake in the CE-Hi sheep from the cold per se. Plasma glucose pool size increased (P < 0.1) in CE-Hi sheep from 1.81 (TN-Low) and 1.83 (TN-Hi) to 2.40 mmol kg−0.75. Plasma glucose entry rates increased (P < 0.001) from 0.91 (TN-Low) to 1.29 (TN-Hi) to 1.78 (CE-Hi) mmol h−1 kg−0.75. Plasma alanine entry rates showed a tendency (P = 0.19) to increase in the CE-Hi sheep. Percentage alanine converted to glucose increased (P < 0.1) from 14.2% (TN-Low) and 13.4% (TN-Hi) to 21.5% (CE-Hi). These results indicate that increased glucose metabolism in cold-exposed sheep is a chronic adaptation. The data also suggest that the rate of alanine conversion to glucose increases during chronic cold exposure. Key words: Alanine, glucose, chronic cold exposure, sheep

Glucose metabolism in lactating reindeer

1976 ◽  
Vol 54 (1) ◽  
pp. 55-64 ◽  
Author(s):  
R. G. White ◽  
J. R. Luick
Keyword(s):  
Plasma Glucose ◽  
Transfer Rate ◽  
Turnover Time ◽  
Pool Size ◽  
Glucose Turnover ◽  
Irreversible Loss ◽  
Domestic Species ◽  
Glucose Transfer ◽  
Glucose Synthesis ◽  
Lactation Cycle

Changes in glucose synthesis during the lactation cycle were estimated in pen-fed and grazing reindeer. The pool size, space, transfer rate, and irreversible loss of glucose were determined using simultaneous injections of [2-3H]glucose and primed infusions of [U-14C]glucose in reindeer lactating for 1–2, 4–5, 8–9, and 12–16 weeks. Glucose transfer rate and irreversible loss were higher during early to midlactation than at other times of the year; maximum estimates were at 8–9 weeks postpartum (July), and a decline was noted at 12–16 weeks (August). During the first 1–2 weeks in pen-fed and 4–5 weeks in grazing reindeer, glucose transfer rate and irreversible loss were almost twice the values reported for reindeer at maintenance. No difference in the irreversible loss of glucose was noted between lactating and non-lactating reindeer at 18–20 weeks postpartum (September), and there is evidence that this may occur as early as 12–16 weeks postpartum. No significant trend was noted in the glucose space throughout lactation; however, a significant increase in plasma glucose concentration and pool size was noted when glucose synthesis was highest (8–9 weeks postpartum). Glucose turnover time was consistently faster (78–88 min) in lactating than in non-lactating reindeer (107–140 min). Reindeer used a smaller proportion of plasma glucose-C for lactose synthesis than did other domestic species. This probably results from the low lactose content of reindeer milk and the relatively low rate of milk secretion.

EFFECT OF INTRARUMINAL INFUSION OF PROPIONIC ACID ON PLASMA METABOLITES IN GOATS

1984 ◽  
Vol 64 (5) ◽  
pp. 295-297 ◽  
Author(s):  
B. EMMANUEL ◽  
J. J. KENNELLY
Keyword(s):  
Key Words ◽  
Propionic Acid ◽  
Plasma Glucose ◽  
Milk Fat ◽  
Plasma Metabolites ◽  
Data Support

Effects of intraruminal infusion of propionic acid at 5.5 and 13.7 g/h on plasma metabolites have been investigated in goats fed a concentrate-roughage ration at 2-h intervals. Propionic acid increased plasma glucose and insulin concentrations, but did not change those of lactate, D(−)-3-hydroxybutyrate and prolactin. Data support the glucogenic theory in relation to low milk fat syndrome. Key words: Metabolites, plasma, goats, propionic acid

THE EFFECT OF BETAMETHASONE ON GLUCOSE PRODUCTION AND ON GLUCONEOGENESIS FROM AMINO ACIDS IN SHEEP

1974 ◽  
Vol 60 (3) ◽  
pp. 455-461 ◽  
Author(s):  
P. E. B. REILLY ◽  
E. J. H. FORD
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Plasma Glucose ◽  
Intramuscular Injection ◽  
Significant Proportion ◽  
Glucose Production ◽  
Entry Rate ◽  
Steroid Administration ◽  
Single Intramuscular Injection ◽  
Mean Glucose

SUMMARY Primed continuous infusions of tracer amounts of [U-14C]glucose and of [U-14C]labelled mixed amino acids were used to measure plasma glucose and amino acid entry rates and to obtain an index of the incorporation of amino acid carbon into glucose by sheep before and 24 h after a single intramuscular injection of betamethasone. Maximum hyperglycaemia occurred 24 h after administration of the steroid, but there was no significant change in arterial amino acid concentration. Mean glucose entry rate was significantly raised 24 h after steroid administration. The rate of incorporation of amino acid carbon into glucose also increased significantly. The increases in plasma glucose concentration and in glucose entry confirm the authors' previous results. The results also indicate that a significant proportion of the additional glucose entry is synthesized from amino acid carbon.

THE POOL SIZE, TURNOVER RATE, AND OXIDATION RATE OF BODY GLUCOSE IN ANESTHETIZED WARM- AND COLD-ACCLIMATED RATS EXPOSED TO A WARM ENVIRONMENT

1959 ◽  
Vol 37 (1) ◽  
pp. 285-295 ◽  
Author(s):  
Florent Depocas
Keyword(s):  
Body Weight ◽  
Plasma Glucose ◽  
Turnover Time ◽  
The Body ◽  
Pool Size ◽  
Glucose Turnover ◽  
Oxidation Rates ◽  
Warm Environment ◽  
Essentially Normal ◽  
The Difference

The size and space of the body glucose pool along with its turnover and oxidation rates have been measured in anesthetized 30° and 6 °C acclimated rats by a method involving continuous intravenous injection of small amounts of D-glucose uniformly labelled with C14 and attainment of relatively constant specific activities of plasma glucose and respiratory CO2. Values of glucose pool space in warm-acclimated rats (essentially normal animals) were in accord with those found in the dog by a similar method. Results obtained on warm-acclimated rats indicated that previous published values of turnover and oxidation rates of glucose for normal rats were high by a factor of approximately 2 to 4. There was, however, close agreement between the values of turnover time of body glucose pool measured by the continuous infusion procedure and those obtained by others with the single intravenous or intraperitoneal injection procedure. In cold-acclimated rats, average absolute values of glucose pool size were significantly smaller than in warm-acclimated rats but the difference was lost when results were related to body weight. Small, non-significant differences in values of glucose pool size per 100 g body weight and in plasma glucose concentration combined to give a significantly larger glucose space in cold-than in warm-acclimated rats. Glucose turnover and oxidation rates, the ratio between these two quantities, and the proportion of respiratory CO2 derived from glucose oxidation were not significantly different in the two groups of rats, thus indicating that cold acclimation is not associated with major alterations in glucose metabolism at least when studied on fully fed anesthetized animals at 30 °C.

Plasma glucose kinetics during prolonged exercise in trained humans when fed carbohydrate

2002 ◽  
Vol 283 (3) ◽  
pp. E573-E577 ◽  
Author(s):  
Damien J. Angus ◽  
Mark A. Febbraio ◽  
Mark Hargreaves
Keyword(s):  
Plasma Glucose ◽  
Cycle Ergometer ◽  
Strenuous Exercise ◽  
Glucose Disposal ◽  
Glucose Kinetics ◽  
Exogenous Glucose ◽  
Appearance Rate ◽  
Volitional Fatigue ◽  
Glucose Output ◽  
Peak Value

Nine endurance-trained men exercised on a cycle ergometer at ∼68% peak O2 uptake to the point of volitional fatigue [232 ± 14 (SE) min] while ingesting an 8% carbohydrate solution to determine how high glucose disposal could increase under physiological conditions. Plasma glucose kinetics were measured using a primed, continuous infusion of [6,6-2H]glucose and the appearance of ingested glucose, assessed from [3-3H]glucose that had been added to the carbohydrate drink. Plasma glucose was increased ( P < 0.05) after 30 min of exercise but thereafter remained at the preexercise level. Glucose appearance rate (Ra) increased throughout exercise, reaching its peak value of 118 ± 7 μmol · kg−1 · min−1 at fatigue, whereas gut Ra increased continuously during exercise, peaking at 105 ± 10 μmol · kg−1 · min−1 at the point of fatigue. In contrast, liver glucose output never rose above resting levels at any time during exercise. Glucose disposal (Rd) increased throughout exercise, reaching a peak value of 118 ± 7 μmol · kg−1 · min−1 at fatigue. If we assume 95% oxidation of glucose Rd, estimated exogenous glucose oxidation at fatigue was 1.36 ± 0.08 g/min. The results of this study demonstrate that glucose uptake increases continuously during prolonged, strenuous exercise when carbohydrate is ingested and does not appear to limit exercise performance.

scholarly journals Effects of carbohydrate ingestion before and during exercise on glucose kinetics and performance

2000 ◽  
Vol 89 (6) ◽  
pp. 2220-2226 ◽  
Author(s):  
Mark A. Febbraio ◽  
Alison Chiu ◽  
Damien J. Angus ◽  
Melissa J. Arkinstall ◽  
John A. Hawley
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Peak Power ◽  
Glucose Oxidation ◽  
Time Trial ◽  
Peak Power Output ◽  
Glucose Kinetics ◽  
Carbohydrate Ingestion ◽  
Total Fat ◽  
And Performance

We investigated the effect of carbohydrate (CHO) ingestion before and during exercise and in combination on glucose kinetics, metabolism and performance in seven trained men, who cycled for 120 min (SS) at ∼63% of peak power output, followed by a 7 kJ/kg body wt time trial (TT). On four separate occasions, subjects received either a placebo beverage before and during SS (PP); placebo 30 min before and 2 g/kg body wt of CHO in a 6.4% CHO solution throughout SS (PC); 2 g/kg body wt of CHO in a 25.7% CHO beverage 30 min before and placebo throughout SS (CP); or 2 g/kg body wt of CHO in a 25.7% CHO beverage 30 min before and 2 g/kg of CHO in a 6.4% CHO solution throughout SS (CC). Ingestion of CC and CP markedly (>8 mM) increased plasma glucose concentration ([glucose]) compared with PP and PC (5 mM). However, plasma [glucose] fell rapidly at the onset of SS so that after 80 min it was similar (6 mM) between all treatments. After this time, plasma [glucose] declined in both PP and CP ( P < 0.05) but was well maintained in both CC and PC. Ingestion of CC and CP increased rates of glucose appearance (Ra) and disappearance (Rd) compared with PP and PC at the onset of, and early during, SS ( P < 0.05). However, late in SS, both glucose Ra and Rd were higher in CC and PC compared with other trials ( P < 0.05). Although calculated rates of glucose oxidation were different when comparing the four trials ( P < 0.05), total CHO oxidation and total fat oxidation were similar. Despite this, TT was improved in CC and PC compared with PP ( P < 0.05). We conclude that 1) preexercise ingestion of CHO improves performance only when CHO ingestion is maintained throughout exercise, and 2) ingestion of CHO during 120 min of cycling improves subsequent TT performance.

Effect of digestible energy intake on glucose synthesis in reindeer and caribou

1976 ◽  
Vol 54 (5) ◽  
pp. 737-751 ◽  
Author(s):  
E. H. McEwan ◽  
Pamela Whitehead ◽  
R. G. White ◽  
J. O. Anvik
Keyword(s):  
Plasma Concentration ◽  
Energy Intake ◽  
Close Correlation ◽  
Turnover Time ◽  
Glucose Turnover ◽  
Irreversible Loss ◽  
Entry Rate ◽  
Digestible Energy ◽  
Multicompartmental Analysis ◽  
Glucose Synthesis

Glucose parameters were estimated by multicompartmental analysis after the single injection of [U-14C] glucose in pen-fed reindeer and caribou. During the rut, the plasma concentration, pool size, space, total entry rate, irreversible loss, and glucose turnover time of male reindeer and caribou declined; all parameters increased significantly after the rut ended and feeding had begun again. In female reindeer and caribou the lowest estimates of glucose pool, space, total entry rate, and irreversible loss were noted during midpregnancy (February–April). During early lactation (May–June) significant increases were noted in total entry rate, irreversible loss, and the plasma concentration of glucose.For non-lactating reindeer and caribou, inflections in relationships between glucose total entry rate and irreversible loss with digestible energy intake were noted at a daily digestible intake of about 195 kcal/W0.75 (where W0.75 = metabolic body weight); three times more glucose was synthesized per unit digestible energy intake above the point of inflection than was synthesized below it. Per unit of protein intake, total entry rate and irreversible loss of glucose for males exceeded that of the females by 4 to 5 mg/W0.75 per minute. In female reindeer and caribou a close correlation was noted between the glucose irreversible loss and total entry rate. Glucose resynthesis was constant at 1.5 mg/W0.75 per minute.

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