scholarly journals Seasonal variations in glucose metabolism of reindeer (Rangifer tarandus L.) estimated with [U-14C]glucose and [3-3H]glucose

1973 ◽  
Vol 29 (2) ◽  
pp. 245-259 ◽  
Author(s):  
J. R. Luick ◽  
S. J. Person ◽  
R. D. Cameron ◽  
R. G. White
Keyword(s):  
Glucose Metabolism ◽  
Transfer Rate ◽  
Rangifer Tarandus ◽  
Extracellular Fluid ◽  
Late Pregnancy ◽  
Subjective Assessment ◽  
Turnover Time ◽  
Pool Size ◽  
Irreversible Loss ◽  
Glucose Transfer

1. The pool size, space and rate of irreversible loss of glucose were estimated with primed infusions of [U-14C]glucose in reindeer cows within 6 h of being taken from outdoor pens or from free grazing in the field.2. In conjunction with primed infusions of [U-14C]glucose, single injections of [3-3H]glucose were also used to estimate pool size, space, transfer rate, and turnover time of glucose.3. Except in a period of severe undernutrition, the concentration of glucose in plasma was higher (range 0·76–1·40 mg/ml) than that recorded for other ruminants.4. The size of the glucose pool (range 8–35 g) varied in parallel with plasma glucose concentration and was generally distributed in a space in excess of the extracellular fluid volume.5. The lowest rates of irreversible loss of glucose (approximately 1·7 mg/min per kg0·75) were measured when cows were in mid pregnancy and when available food was scarce; the highest rate (5·5 mg/min per kg0·75) was found in cows during mid summer.6. Changes in irreversible loss and transfer rate of glucose are interpreted in relation to changes in body composition (estimated in a parallel study), subjective assessment of available food and factors known to control glucose metabolism in other ruminants.7. The difference between glucose transfer rate and rate of irreversible loss of glucose was used as an index of the rate of resynthesis of glucose from products of glucose catabolism. The rates of glucose resynthesis were highest during a period of rapid growth (4·52 mg/min per kg0·75 or 45% of the glucose transfer rate) and in mid and late pregnancy (respectively 4·14 and 4·28 mg/min per kg0·75 or 71 and 59% of the transfer rate).

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.

Glucose biokinetics in sheep

1961 ◽  
Vol 201 (4) ◽  
pp. 639-644 ◽  
Author(s):  
D. S. Kronfeld ◽  
M. G. Simesen
Keyword(s):  
Glucose Metabolism ◽  
Transfer Rate ◽  
Transfer Rates ◽  
Glucose Transfer

The transfer rate of the glucose pool in sheep was estimated by methods using labeled glucose. Transfer rates ranged from 0.28 to 0.39 g/hr/kg3/4 when estimated 1 or 16 hr after feeding, but were only 0.18 and 0.20 g/hr/kg3/4 when estimated 96 hr after feeding. Comparable values calculated from data in the literature for rats, dogs, and man range from 0.25 to 0.40 g/hr/kg3/4 at 16 hr after feeding, although they are higher for rats only 4 hr after feeding (0.89 g/hr/kg3/4). Comparison of postabsorptive values (4 hr in rats, 16 hr in sheep) or fasting values (16 hr in rats, dogs, and man, 96 hr in sheep) suggests that the over-all rate of glucose metabolism is lower in sheep.

Exchangeable sodium pool size and turnover in relation to diet in reindeer

1982 ◽  
Vol 60 (4) ◽  
pp. 603-610 ◽  
Author(s):  
H. Staaland ◽  
D. F. Holleman ◽  
J. R. Luick ◽  
R. G. White
Keyword(s):  
Body Weight ◽  
Transfer Rate ◽  
Rangifer Tarandus ◽  
Mammalian Species ◽  
Pool Size ◽  
Transfer Rates ◽  
High Sodium ◽  
Equal Importance ◽  
Marked Decline ◽  
High Sodium Diet

Sodium pool size and transfer rate was estimated in reindeer (Rangifer tarandus L.) using intravenous and intraluminal injections of 22NaCl. Body water pool size and water transfer rate was estimated with 3HOH. Reindeer were consuming diets high in sodium (Na) and potassium (K) (commercial livestock ration), low in Na and high in K (summer grazing), and low in Na and K (lichens). The exchangeable Na pool size (milliequivalents per kilogram body weight) in reindeer given the high sodium diet (61 ± 2) was similar to other mammalian species. A marked decline in the pool (to 36 ± 3) was noted when reindeer were grazing summer vegetation in central Alaska and the Na pool was also low (46 ± 5) when they were fed lichens. Concentrations of Na in plasma, saliva, urine, and feces were directly correlated with the exchangeable Na pool size. Sodium transfer rates for reindeer given the high Na diet or grazing were two- to three-fold higher than daily Na intake rates. Loss of Na in feces and urine were of roughly equal importance in reindeer fed lichens or at pasture. Signs of Na insufficiency indicated by a salivary Na:K ratio of less than 2:1 were noted when the Na pool size declined below 40 mequiv./kg body weight. Evidence is presented for an extremely rapid replenishment of the Na pool following Na supplement of the diet.

Glucose biokinetics in normal and ketotic cows

1959 ◽  
Vol 14 (6) ◽  
pp. 1026-1028 ◽  
Author(s):  
D. S. Kronfeld ◽  
E. G. Tombropoulos ◽  
Max Kleiber
Keyword(s):  
Transfer Rate ◽  
Extracellular Volume ◽  
Turnover Time ◽  
Intracellular Compartment

The size, turnover time and transfer rate of the glucose pool were estimated with glucose–C14 in normal and ketotic cows. The size and turnover time of the pool were both about 1/5 greater in the ketotic than in the normal cows, so that the transfer rate remained similar, being about 1 gm/min. The hypoglycemia which is characteristic of the disease appeared to be associated with an expansion of the glucose space, which in the normal cows approximated the extracellular volume, into the intracellular compartment of the ketotic cows. These results do not favor theories of bovine ketosis which presume a shortage of body glucose. Submitted on June 25, 1959

Alterations in basal glucose metabolism during late pregnancy in the conscious dog

2000 ◽  
Vol 279 (5) ◽  
pp. E1166-E1177 ◽  
Author(s):  
Cynthia C. Connolly ◽  
Linda C. Holste ◽  
Lisa N. Aglione ◽  
Doss W. Neal ◽  
D. Brooks Lacy ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Hepatic Glucose Production ◽  
Late Pregnancy ◽  
Nonesterified Fatty Acid ◽  
Acid Uptake ◽  
Substrate Uptake ◽  
Hepatic Glucose Output ◽  
Hepatic Glucose ◽  
Glucose Output ◽  
In Pregnancy

We assessed basal glucose metabolism in 16 female nonpregnant (NP) and 16 late-pregnant (P) conscious, 18-h-fasted dogs that had catheters inserted into the hepatic and portal veins and femoral artery ∼17 days before the experiment. Pregnancy resulted in lower arterial plasma insulin (11 ± 1 and 4 ± 1 μU/ml in NP and P, respectively, P < 0.05), but plasma glucose (5.9 ± 0.1 and 5.6 ± 0.1 mg/dl in NP and P, respectively) and glucagon (39 ± 3 and 36 ± 2 pg/ml in NP and P, respectively) were not different. Net hepatic glucose output was greater in pregnancy (42.1 ± 3.1 and 56.7 ± 4.0 μmol · 100 g liver−1· min−1in NP and P, respectively, P < 0.05). Total net hepatic gluconeogenic substrate uptake (lactate, alanine, glycerol, and amino acids), a close estimate of the gluconeogenic rate, was not different between the groups (20.6 ± 2.8 and 21.2 ± 1.8 μmol · 100 g liver−1· min−1in NP and P, respectively), indicating that the increment in net hepatic glucose output resulted from an increase in the contribution of glycogenolytically derived glucose. However, total glycogenolysis was not altered in pregnancy. Ketogenesis was enhanced nearly threefold by pregnancy (6.9 ± 1.2 and 18.2 ± 3.4 μmol · 100 g liver−1· min−1in NP and P, respectively), despite equivalent net hepatic nonesterified fatty acid uptake. Thus late pregnancy in the dog is not accompanied by changes in the absolute rates of gluconeogenesis or glycogenolysis. Rather, repartitioning of the glucose released from glycogen is responsible for the increase in hepatic glucose production.

scholarly journals Glucose partitioning in the pregnant ewe: Effects of undernutrition and exercise

1990 ◽  
Vol 64 (2) ◽  
pp. 449-462 ◽  
Author(s):  
B. J. Leury ◽  
A. R. Bird ◽  
K. D. Chandler ◽  
A. W. Bell
Keyword(s):  
Glucose Uptake ◽  
Energy Requirement ◽  
Live Weight ◽  
Late Pregnancy ◽  
Maternal Blood ◽  
Whole Body ◽  
Entry Rate ◽  
Glucose Transfer ◽  
Glucose Supply ◽  
Maternal Glucose

Maternal whole-body glucose entry rate and uterine and umbilical net uptakes of glucose and oxygen were measured in single-pregnant ewes which were either well-fed throughout, or fed at 0.3–0.4 predicted energy requirement for 7–21 d during late pregnancy. All ewes were studied while standing at rest and then while walking on a treadmill at 0.7 m/s on a 10° slope for 60 min. Underfed ewes suffered significant decreases in live weight and had lower fetal, but not placental, weights at 140–144 d gestation. Undernutrition also caused large decreases in maternal glycaemia and glucose entry rate, which were associated with equally large decreases in uterine and umbilical net uptakes and O2 quotients of glucose, and with a decrease in placental glucose transfer capacity. Exercise caused increases in maternal blood concentration, entry rate and uterine net uptake of glucose, the magnitudes of which were not significantly affected by plane of nutrition. Umbilical glucose uptake and placental glucose transfer capacity increased during exercise in underfed but not fed ewes. The fractional distribution of maternal glucose to the pregnant uterus, and of uterine glucose uptake to the fetus, were unaltered by undernutrition; during exercise, a disproportionately small fraction of the increased maternal glucose supply went to the uterus. The results confirm that the ovine conceptus responds to nutritional reduction in maternal glucose availability in a manner similar to non-uterine maternal tissues. Major reductions in glucose supply appear to override putative glucose-sparing mechanisms which may operate to favour the conceptus in better-nourished animals.

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.

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.

The effect of Pyridoxine on Oxalate Dynamics in three Cases of Primary Hyperoxaluria (with Glycollic Aciduria)

1985 ◽  
Vol 69 (1) ◽  
pp. 87-90 ◽  
Author(s):  
R. W. E. Watts ◽  
N. Veall ◽  
P. Purkiss ◽  
M. A. Mansell ◽  
E. F. Haywood
Keyword(s):  
Accumulation Rate ◽  
Extracellular Fluid ◽  
Primary Hyperoxaluria ◽  
Pool Size ◽  
Type I ◽  
Total Clearance ◽  
Biochemical Basis ◽  
Oxalate Concentration ◽  
Measured Glomerular Filtration Rate ◽  
Metabolic Pool

1. We have measured glomerular filtration rate (GFR), extracellular fluid volume (ECF), oxalate distribution volume (OxDV), plasma oxalate concentration (POx.), plasma total clearance of oxalate (PCOx.), oxalate metabolic pool size [(OxDV) × (POx.)], renal clearance of oxalate (RCOx.), oxalate excretion, tissue clearance of oxalate (TCOx.) and tissue oxalate accumulation rate [(TOx.A) = (TCOx.) × (POx.)] in three patients with type I primary hyperoxaluria (hyperoxaluria with hypergrycollic aciduria) when they were taking pyridoxine and after discontinuation of the vitamin. 2. Seven days after stopping pyridoxine the plasma oxalate concentration, oxalate metabolic pool size and the urinary excretion of oxalate had all increased between seven- and eight-fold in two of the patients. The third patient showed no changes on stopping pyridoxine. 3. These results support the view that pyridoxine acts by reducing oxalate biosynthesis in some patients with type I primary hyperoxaluria. 4. The possible biochemical basis for this effect is discussed.

scholarly journals Determination of Bile Acid Pool Size, Turnover Time, and Distribution of Male Broiler Chicks During the First

1987 ◽  
Vol 66 (11) ◽  
pp. 1853-1858 ◽  
Author(s):  
JACK GREEN ◽  
THOMAS KELLOGG ◽  
ROBERT KEIRS ◽  
ROBERT COOPER
Keyword(s):  
Bile Acid ◽  
Turnover Time ◽  
Pool Size ◽  
Broiler Chicks ◽  
Bile Acid Pool ◽  
Acid Pool ◽  
Bile Acid Pool Size
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