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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The secretions of the pancreas drain into the portal vein just upstream of the liver. This anatomical arrangement is an important component of hepatic function since the pancreatic hormones are key regulators of intermediary metabolism in the liver. In response to moderate-intensity exercise, the secretion of glucagon and insulin from the pancreas generally increase and decrease, respectively. This element of the endocrine response to exercise is critical to the maintenance of glucose homeostasis during exercise. The rise in glucagon and fall in insulin are important for the stimulation of hepatic glycogenolysis. The glucagon response is essential for the exercise-induced increase in gluconeogenesis. In addition, glucagon and insulin are also important to the increase in hepatic fat oxidation during exercise. The fall in insulin enhances the mobilization of NEFA's from adipose tissue and as a result the availability of NEFA's to the liver. The increase in glucagon enhances the oxidation of these NEFA's by stimulating pathways for fat oxidation inside the liver. Hepatic fractional amino acid extraction is increased by glucagon action during exercise. Moreover, the increase in glucagon facilitates the channeling of amino acid carbons to glucose and may play a role in disposal of associated nitrogen. Because of the important roles that glucagon and insulin play, any physiological or pathological condition that affects their secretion or efficacy will impact on the metabolic response to exercise.
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PMID:Role of the endocrine pancreas in control of fuel metabolism by the liver during exercise. 858 Oct 91

Twenty-four Suffolk lambs (average BW 38 +/- 2.7 kg; 16 ewes and 8 wethers) were fed either a corn-cottonseed hull-based control diet (CON) or CON plus 250 ppb of Cr as chromium tripicolinate (CrPic). Lambs were penned in groups of three and ADG and DMI were measured through d 85 of the experiment. Jugular blood samples were obtained during wk 2, 7, and 11. An i.v. glucose tolerance test (IVGTT; 500 mg of glucose/kg BW) and an i.v. insulin challenge test (IVICT; .1 IU of ovine insulin/kg BW) were performed during wk 2 and 10 of the trial. This was followed by a N balance trial during wk 3 and 11. Wethers were slaughtered at the end of the experiment and carcass characteristics determined. No differences (P > .10) were observed between dietary treatments in DMI, ADG, or N balance; however, the CrPic-fed wethers had 18% less fat over the 10th rib (P = .082) and a lower yield grade (P = .014). Plasma NEFA was lower throughout the trial (P < .03) and cholesterol was 17% lower during wk 2 (P < .02) in lambs fed CrPic. There were no differences due to diet (P > .10) in plasma concentrations of urea N, glucose, albumin, total protein, insulin, glucagon, triiodothyronine, or thyroxine. Glucose clearance rate and half-life during the IVGTT and IVICT did not differ (P > .10) between CON and CrPic groups; however, during the IVGTT on wk 2, plasma insulin was elevated (P < .05) and glucose reduced (P = .067) in the lambs fed CrPic. Supplemental CrPic seems to influence metabolic measurements that may affect performance of growing lambs.
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PMID:Influence of chromium tripicolinate on glucose metabolism and nutrient partitioning in growing lambs. 858 60

Twelve light horse mares were fed a control diet that provided 100% of their maintenance protein and energy requirements for 7 d and were then either continued on the control diet or totally deprived of feed (with access to water) for 3 d . Plasma samples were drawn twice daily throughout the experiment, at 15-min intervals for 9 h beginning 45 h after feed removal, and at 10-min intervals around an exercise bout beginning 73 h after feed removal. Feed deprivation increased (P < or = .06) whole blood beta-hydroxybutyrate and plasma NEFA, urea N, L-lactate, and glucagon concentrations, decreased (P = .02) IGF-I concentrations, and did not change (P > .1) plasma glucose insulin, prolactin, triiodothyronine, and thyroxine concentrations. Exercise increased (P < .05) plasma NEFA, prolactin, and growth hormone (GH) concentrations in all mares. Plasma NEFA concentrations increased (P < .001) after exercise and remained increased in fed mares, but rapidly decreased in deprived mares (time x diet interaction, P = .006). Plasma glucose concentrations following exercise increased in deprived mares but decreased in fed mares (time x diet interaction, P = .07). The plasma prolactin response after exercise also differed between groups (P = .09). Feed-deprived mares had greater (P = .02) plasma GH concentrations before exercise (73 h after feed withdrawal) and had a greater (P < .001) GH peak at 10 min after initiation of exercise. The increase in secretion rate o GH due to feed deprivation in these mares was similar to that reported for other domestic species but was not nearly as great in magnitude.
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PMID:Feed deprivation of mares: plasma metabolite and hormonal concentrations and responses to exercise. 865 46

Two diets consisting of bermudagrass hay and a corn-cottonseed hull-based supplement were formulated to provide either 100% (control) or 50% (restricted) of the protein and energy requirements for maintenance for mature mares. Twelve light horse mares were fed the control diet for 7 d, and then at 0800 on d 0, six mares were switched to the restricted diet. All diets were fed as two equally sized meals at 0800 and 1600. At 0800 on d 7, mares receiving the restricted diet were switched back to the control diet. Relative to control mares, mares switched to the restricted diet had reduced plasma concentrations of glucose (P = .005) and insulin (P = .09) in response to the two restricted meals on d 0. However, concentrations of both glucose and insulin returned to control levels (P > .1) within 1 h after the consumption of the control diet on d 7. Dietary restriction increased (P = .009) plasma NEFA concentrations within the first 24 h, and NEFA concentrations remained elevated (P < .001) in restricted mares until the mares were returned to the control diet on d 7. Meal-induced increases (P < .05) in plasma concentrations of glucose, insulin, urea N, glucagon, and thyroxine were observed. These results emphasize the importance of early sampling when monitoring plasma constituents during nutrient alterations and indicate that prefeeding responses of plasma constituents alone may not fully explain the metabolic consequences of nutrient restriction.
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PMID:Dietary protein and energy restriction in mares: rapid changes in plasma metabolite and hormone concentrations during dietary alteration. 879 Dec 5

The aim of this study was to investigate the metabolic effects of abdominal versus vaginal hysterectomy with specific regard to perioperative glucose metabolism. Fourteen patients received either abdominal (AH, n = 7) or vaginal hysterectomy (VH, n = 7). Hepatic glucose production was measured before and 2.5 h after the operation by stable isotope technique ([6,6-2H2]-glucose). Metabolic substrates (glucose, lactate, nonesterified fatty acids [NEFA], beta-hydroxybutyrate) and hormones (insulin, glucagon, cortisol, catecholamines) were determined pre-, intra-, and postoperatively. VH induced a higher postoperative glucose concentration than the abdominal approach (VH, 148 +/- 25 mg/dL; AH, 111 +/- 16 mg/dL; P < 0.05). Since postoperative enhancement of hepatic glucose production was comparable in both groups, glucose clearance was lower after the vaginal procedure (VH, 1.7 +/- 0.3 mL.kg-1.min-1; AH, 2.1 +/- 0.3 mL.kg-1.min-1; P < 0.05). NEFA, beta-hydroxybutyrate, and catecholamines similarily increased after surgery. Cortisol levels were more increased after VH (VH, 80 +/- 26 micrograms/dL; AH, 37 +/- 14 micrograms/dL; P < 0.001). Lactate, glucagon, and insulin concentrations did not change perioperatively. The more pronounced hyperglycemic response to VH was due to lower peripheral glucose use caused by higher postoperative cortisol values. The mechanisms responsible for this marked cortisol enhancement after the vaginal operation as well as the clinical significance for patients with preexisting impaired carbohydrate tolerance, however, remained unclear and warrant further investigation.
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PMID:Influence of vaginal versus abdominal hysterectomy on perioperative glucose metabolism. 889 74

To investigate whether recombinant human insulin-like growth factor-I (rhIGF-I) has direct effects on the insulin requirement to maintain euglycemia independent of the growth hormone (GH) level, nine subjects with insulin-dependent diabetes mellitus ([IDDM] seven females; median (range) age, duration of diabetes, and hemoglobin A1C [HbA1C], 16.9 (12.5 to 21.9) years, 11.8 (4.6 to 16.8) years, and 9.8% (7.9% to 14.1%), respectively) underwent two euglycemic studies (6:00 PM to 8:00 AM) after double-blind subcutaneous administration of rhIGF-I/placebo (40 microg/kg). Octreotide infusion (300 ng/kg/h) suppressed endogenous GH, and three identical discrete GH pulses were infused on both nights. Variable-rate insulin infusion maintained euglycemia. Samples were taken every 15 minutes (glucose and GH), 30 minutes (insulin and intermediate metabolites), and 60 minutes (IGF-I and nonesterified fatty acids [NEFA]). Variables were analyzed during the steady-state period of euglycemia (4:00 to 8:00 AM). Data are expressed as the mean +/- SEM. The insulin infusion rate and free-insulin level were both significantly reduced after rhIGF-I administration (0.13 +/- 0.03 v placebo 0.23 +/- 0.05 mU/kg/min, P = .04, and 8.4 +/- 1.3 v placebo 12.1 +/- 1.4 mU/L, P = .03, respectively). GH pulse-related changes in the insulin requirement observed after placebo were not present after rhIGF-I. Glucagon levels were equally suppressed on both nights. Insulin clearance was not altered after rhIGF-I administration. NEFA and ketone levels also were not different on the 2 nights. In conclusion, in adolescents and young adults with diabetes, rhIGF-I administration directly affected insulin requirements independent of GH levels, but had no effect on fatty acid or ketone levels. This difference is related to the abolition of changes in the insulin requirement after GH pulses, and would suggest a complex interaction between GH and IGF-I on insulin action.
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PMID:Recombinant human insulin-like growth factor-I abolishes changes in insulin requirements consequent upon growth hormone pulsatility in young adults with type I diabetes mellitus. 944 Apr 74

We performed prospective study to determine whether the increase of calories with preoperative oral intake will prevent ketosis due to preoperative starvation in children receiving afternoon surgery. Twenty five children (aged 3 to 9 years) for elective minor surgery under general anesthesia with sevoflurane and nitrous oxide were divided into morning surgery group and afternoon surgery group, and the latter was divided into 2 groups according to calories contained in the clear fluid. The calorie of the clear fluid in the afternoon group P was 0.24 kcal.ml-1, and that in the afternoon group A was 0.48 kcal.ml-1. The calorie of the clear fluid in the morning group was 0.48 kcal. ml-1. The levels of blood glucose, blood ketone body, plasma free fatty acids (NEFA), insulin, glucagon and cortisol were measured before and during intravenous infusion in three groups. The urinary catecholamine excretion was measured in the urine collected from 18:00 on the day before operation day until the start of anesthesia. There were no significant differences in the levels of blood glucose, NEFA, insulin, glucagon, cortisol and urinary catecholamine excretion. But the level of blood ketone body only in the afternoon group P was significantly higher than that in the morning group. But the levels of NEFA before infusion were higher than average in 40-60 percent of patients of each group. These data suggest that the increasing preoperative calories with oral intake will prevent ketosis due to preoperative starvation in the afternoon group as well as in the morning group. But the short duration of starvation only can not prevent lipolysis completely.
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PMID:[The effect of calories of preoperative oral intake on the glucose metabolic response in children]. 1033 32

The effects of feed restriction, cold exposure, and the initiation of feeding on blood glucose metabolism, other blood metabolites, hormones, and tissue responsiveness and sensitivity to insulin were measured in sheep. The sheep consumed orchardgrass hay ad libitum (AL) or were restricted to 82% of the ME requirement for maintenance (RE) and were exposed to a thermoneutral (20 degrees C) or a cold environment (2 degrees C). An isotope dilution method and a glucose clamp approach were applied to determine blood glucose metabolism and insulin action, respectively. Plasma NEFA and insulin concentrations were influenced by feed restriction. Concentrations of plasma glucose, NEFA, insulin, and glucagon were influenced by cold exposure. Plasma NEFA concentration for RE decreased after the initiation of feeding and plasma insulin concentration increased transiently for all treatments. [U-13C]Glucose was continuously infused for 8 or 7 h after a priming injection starting 3 h before the initiation of either feeding or insulin infusion, respectively. When responses to feeding were studied, blood glucose turnover rate was less (P < .001) for RE than for AL, and it was greater (P < .001) during cold exposure than in the thermoneutral environment. The rate changed little after the initiation of feeding. For the glucose clamp approach, insulin was infused over four sequential 1-h periods at rates from .64 to 10 mU x kg BW(-1) x min(-1), with concomitant glucose infusion to maintain preinfusion plasma glucose concentrations. The rates of glucose infusion and blood glucose turnover increased (P < .001) dose-dependently with insulin infusion rate. The maximal glucose infusion rate was greater (P < .05) for RE than for AL and was greater (P < .001) during cold exposure than in the thermoneutral environment. The plasma insulin concentration at half-maximal glucose infusion rate was lower (P < .1) during cold exposure. Blood glucose turnover rate tended to be greater (P = .10) for RE than for AL, and it was greater (P < .001) during cold exposure than in the thermoneutral environment. The ratio of endogenous production to utilization of glucose was suppressed by insulin infusion. In sheep fed a roughage diet, blood glucose turnover rate seems to be influenced by both intake level and environmental temperature, but not by the act of feeding. Moreover, the action of insulin on glucose metabolism is enhanced during cold exposure, and the effect of feed restriction is somewhat enhanced.
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PMID:Effects of feed restriction and cold exposure on glucose metabolism in response to feeding and insulin in sheep. 1049 66

Low muscle glycogen at the beginning of exercise may adversely affect performance, increase protein degradation and contribute to the onset of fatigue. As horses are sometimes required to compete on consecutive days both in racing and endurance types of competition, optimal muscle glycogen repletion may improve performance on the day following a race day. The purpose of this experiment was to study the effects of fat supplementation on repletion of muscle glycogen. Twelve Finnhorses performed an exercise test on a treadmill, and 2 and 4 h later they received hay and concentrate (Trial A). Two weeks later these horses performed the same exercise test and were fed the same diet supplemented with either 1000 g of carbohydrate or 400 g of vegetable oil (Trial B). A third trial (Trial C) was 3 weeks later, identical to Trial B, except that the fat group had already been adapted to dietary fat for 3 weeks. Blood samples were analysed for lactate, glucose, glycerol, triglycerides, NEFA, cholesterol, beta-OH-butyrate, insulin and glucagon and muscle samples were analysed for glycogen and triglycerides. The results indicate that in horses not adapted to fat feeding, fat supplementation slows the rate of muscle glycogen repletion, and that after an adaptation period, fat supplementation does not alter the rate of muscle glycogen repletion compared to the rate with a normal diet.
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PMID:Effect of a post exercise fat-supplemented diet on muscle glycogen repletion. 1065 6

The effect of feed intake level (.6, 1.0, and 1.6 x maintenance energy and protein requirements, M) on splanchnic (portal-drained viscera [PDV] plus liver) metabolism was evaluated in six multicatheterized beef steers (398 +/- 27 kg), using a double 3 x 3 Latin square design. On the last day of each 21-d experimental period, six hourly blood samples were collected from arterial, portal, and hepatic vessels. Due to catheter patency, PDV fluxes were measured on five steers, and liver and splanchnic fluxes on four steers. Increasing intake elevated (P < .01) splanchnic release of total (T) amino acids (AA), through increases (P < .01) in PDV release of both essential (E) and nonessential (NE) AA, in spite of a tendency (P < .20) for increased liver removal of NEAA. The PDV release of AA N represented 27 and 51% of digested N for 1.0 and 1.6 x M, respectively. At 1.0 and 1.6 x M, the liver removed 34% of total AA released by the PDV. For individual AA, portal flux of most EAA increased (P < .05) with feed intake, and the increase (P < .10) in splanchnic flux was accompanied by increased arterial concentration for all EAA except histidine, lysine, and methionine. This suggests that these might be limiting AA for this diet. On a net basis, most individual NEAA were released by the PDV except glutamate and glutamine, which were removed by the digestive tract. There was a net removal of NEAA by the liver, except for aspartate and especially glutamate, which were released. Ammonia release by the PDV tended (P < .20) to increase with intake and represented 69, 53, and 45% of digested N at .6, 1.0, and 1.6 x M, respectively. Urea removed by the PDV, unaffected by intake, represented 32, 33, and 21% of the digested N. Arterial glucose concentration increased linearly (P < .01) with greater intake, whereas net liver and splanchnic glucose release increased in a quadratic (P < .05) manner. Net PDV glucose release represented 26% of net glucose hepatic release at 1.6 x M. Intake elevated (P < .10) both insulin and glucagon arterial concentrations, resulting from a larger increment of portal release (P < .01) than hepatic removal (P < .05). Intake-based variations in IGF-I and NEFA arterial concentrations (P < .05) were not related to changes in splanchnic metabolism. These results clearly show the crucial role of the splanchnic tissues in regulating the profile and quantity of AA and concentrations of glucose and pancreatic hormones reaching peripheral tissues.
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PMID:The effect of feed intake level on splanchnic metabolism in growing beef steers. 1078 2


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