Effects of Intravenous versus intragastric glucose pretreatment on triglyceride secretion by perfused livers of fed rats

1981 ◽  
Vol 59 (8) ◽  
pp. 580-585 ◽  
Author(s):  
D. J. Semple ◽  
B. M. Wolfe
Keyword(s):  
Porcine Insulin ◽  
Water Soluble ◽  
Hepatic Glycogen ◽  
Glucose Load ◽  
Hepatic Triglyceride ◽  
Intravenous Glucose ◽  
Total Liver ◽  
Triglyceride Secretion ◽  
The Mean

The effects of the route of administration of 450 mg [U-14C]glucose to 250-g fed rats in vivo on the subsequent release of triglycerides from the perfused liver was studied. Livers were perfused for 180 min using a nonrecycling medium containing 10 mM glucose, 2 mM lactate, 0.2 mM pyruvate, and 100 μU/mL porcine insulin. Biopsies were obtained at the beginning and end of the perfusions. The perfusate was collected and the secreted triglycerides were analyzed.Slower absorption of the intragastric glucose load contrasted with the rapid entry of the intravenous load; however, the total liver counts were not significantly affected by the route of glucose delivery. Hepatic glycogen concentration was also not significantly different, but the percent of total liver counts which was present in glycogen was significantly higher after intravenous glucose. The majority of the radioactivity in the livers of both groups of rats was present in water-soluble metabolites, with lesser amounts in triglycerides and phospholipids. Radioactivity in hepatic triglycerides declined significantly during perfusion only in the rats which had received glucose intravenously. The mean rate of triglyceride secretion from the livers of rats receiving the glucose intravenously was significantly lower than that of the rats receiving glucose intragastrically (0.21 ± 0.05 vs. 0.97 ± 0.28 mg/g liver per 180 min, p < 0.05). The route of glucose administration affects both entry of glucose into the blood and subsequent hepatic triglyceride metabolism and secretion.

Hepatic glycogen in humans. I. Direct formation after oral and intravenous glucose or after a 24-h fast

1989 ◽  
Vol 257 (2) ◽  
pp. E145-E157 ◽  
Author(s):  
J. Radziuk
Keyword(s):  
Glucose Infusion ◽  
Hepatic Glycogen ◽  
Oral Glucose ◽  
Metabolic Clearance ◽  
Glucose Load ◽  
Fasting Period ◽  
Intravenous Glucose ◽  
Glucose Loading ◽  
Constant Rate ◽  
Direct Formation

The formation of hepatic glycogen by the direct pathway is assessed in humans 1) after a 12-h fast and oral loading (100 g) or 2) intravenous infusion (90 g) and 3) after a 24-h fast and the same oral glucose load. The methodology used is based on the double tracer method. [3–3H]glucose is infused at a constant rate for the determination of the metabolic clearance of glucose. [1–14C]glucose is administered with the glucose load. One hour after absorption or the intravenous glucose infusion is terminated, a glucagon infusion is initiated to mobilize the glycogen labeled with [1-14C]glucose and formed during the absorptive period. At this time a third tracer, [6-3H]glucose, is administered to measure glucose clearance. It was found that after the 12-h fast and oral glucose loading 7.2 +/- 1.1 g of hepatic glycogen appears to be formed directly from glucose compared with 8.4 +/- 1.0 g after the same load and a 24-h fast and 8.5 +/- 0.4 g after a 12-h fast and an equivalent intravenous glucose infusion. When the amount of label ([14C]glucose) mobilized that was not corrected for metabolic recycling was calculated, the data suggested that the amount of glycogen formed by gluconeogenic pathways was probably at least equal to that formed by direct uptake. It was also approximately 60% greater after a 24-h fast. It can be concluded that the amount of hepatic glycogen formed directly from glucose during glucose loading is not significantly altered by the route of entry or the extension of the fasting period to 24 h. The data suggest, however, that gluconeogenetic formation of glycogen increases with fasting.

Mechanism of delayed hepatic glycogen synthesis after an oral galactose load vs. an oral glucose load in adult rats

1992 ◽  
Vol 263 (1) ◽  
pp. E42-E49 ◽  
Author(s):  
C. B. Niewoehner ◽  
B. Neil
Keyword(s):  
Glucose Concentration ◽  
Glycogen Synthesis ◽  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Oral Glucose ◽  
Glucose Load ◽  
Adult Rats ◽  
Glycogen Accumulation ◽  
Glucose Administration

We have compared the effects of administration of oral galactose or glucose (1 g/kg) to 24-h fasted rats to examine the mechanism by which galactose regulates its own incorporation into liver glycogen in vivo. Liver glycogen increased to a maximum more slowly after galactose than after glucose administration (0.14 vs. 0.29 mumol.g liver-1.min-1). Glycogen accumulation after the galactose load was 70% of that after the glucose load (149 vs. 214 mumol), and the net increase in liver glycogen represented the same proportion (24 vs. 22%) of added carbohydrate after urinary loss of galactose was accounted for. Slower glycogen accumulation after galactose vs. glucose loading could not be explained by galactosuria, by differences in the active forms of synthase or phosphorylase, by end product (glycogen) inhibition of synthase phosphatase, or by different concentrations of the known allosteric effectors of synthase R plus I and phosphorylase a. Similar increases in glucose 6-phosphate were observed after both hexoses. AMP and ADP increased only transiently after galactose administration, and ATP, UTP, and Pi concentrations were unchanged. The UDP-glucose concentration decreased, whereas the UDP-galactose concentration increased two- to threefold after galactose but not glucose administration. The UDP-glucose pyrophosphorylase reaction is inhibited competitively by UDP-galactose. This could explain the decreased UDP-glucose concentration and the reduced rate of glycogen synthesis after galactose was given.

Measurement of hepatic Ra UDP-glucose in vivo in rats: relation to glycogen deposition and labeling patterns

1997 ◽  
Vol 272 (1) ◽  
pp. E155-E162 ◽  
Author(s):  
M. K. Hellerstein ◽  
A. Letscher ◽  
J. M. Schwarz ◽  
D. Cesar ◽  
C. H. Shackleton ◽  
...  
Keyword(s):  
Liver Glycogen ◽  
Hepatic Glycogen ◽  
Distribution Analysis ◽  
Basic Principles ◽  
Intravenous Glucose ◽  
Isotopic Method ◽  
Mass Isotopomer Distribution Analysis ◽  
Common Precursor ◽  
Glycogen Deposition

We previously described an isotopic method for quantifying the rate of appearance of hepatic UDP-glucose (Ra UDP-Glc) and the direct entry of glucose into hepatic UDP-Glc in humans. Here, the method is tested in depth in rats. The basic principles are that dilution of labeled galactose in hepatic UDP-Glc, sampled noninvasively by the xenobiotic glucuronate (GlcUA) method, reveals Ra UDP-Glc. First, labeling patterns in secreted acetaminophen-GlcUA were compared with hepatic glycogen and plasma glucose by use of mass isotopomer distribution analysis from [2-(13)C]glycerol. Labeling was consistent with common precursor pools of glucose 6-phosphate and triose-phosphate for all end products studied in fasted and in intravenous glucose- and fructose-infused states. Next, [1-(3)H]galactose was administered. After a 24-h fast, Ra UDP-Glc was 25.0 +/- 1.7 mumol.kg body wt-1.min-1 and rose to 57.7 and 72.7 mumol.kg-1.min-1 at intravenous glucose infusion rates of 111 and 167-194 mumol.kg-1.min-1, respectively. Liver glycogen deposition correlated closely with Ra UDP-Glc (R2 = 0.76), although the turnover value was approximately 50% higher than the net deposition rate. In conclusion, the turnover of an intrahepatic metabolite, UDP-Glc, can be measured noninvasively, and Ra UDP-Glc correlates with liver glycogen deposition in rats.

Glucose-stimulated insulin secretion suppresses hepatic triglyceride-rich lipoprotein and apoB production

2000 ◽  
Vol 279 (5) ◽  
pp. E1003-E1011 ◽  
Author(s):  
Doru V. Chirieac ◽  
Lucian R. Chirieac ◽  
James P. Corsetti ◽  
Joanne Cianci ◽  
Charles E. Sparks ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Serum Triglyceride ◽  
Hepatic Triglyceride ◽  
Triglyceride Secretion ◽  
Triglyceride Rich Lipoprotein ◽  
Apob Secretion ◽  
Glucose Stimulated Insulin Secretion

The current study assessed in vivo the effect of insulin on triglyceride-rich lipoprotein (TRL) production by rat liver. Hepatic triglyceride and apolipoprotein B (apoB) production were measured in anesthetized, fasted rats injected intravenously with Triton WR-1339 (400 mg/kg). After intravascular catabolism was blocked by detergent treatment, glucose (500 mg/kg) was injected to elicit insulin secretion, and serum triglyceride and apoB accumulation were monitored over the next 3 h. In glucose-injected rats, triglyceride secretion averaged 22.5 ± 2.1 μg · ml−1· min−1, which was significantly less by 30% than that observed in saline-injected rats, which averaged 32.1 ± 1.4 μg · ml−1· min−1. ApoB secretion was also significantly reduced by 66% in glucose-injected rats. ApoB immunoblotting indicated that both B100 and B48 production were significantly reduced after glucose injection. Results support the conclusion that insulin acts in vivo to suppress hepatic very low density lipoprotein (VLDL) triglyceride and apoB secretion and strengthen the concept of a regulatory role for insulin in VLDL metabolism postprandially.

Hepatic glycogen in humans. II. Gluconeogenetic formation after oral and intravenous glucose

1989 ◽  
Vol 257 (2) ◽  
pp. E158-E169 ◽  
Author(s):  
J. Radziuk
Keyword(s):  
Human Subjects ◽  
Glucose Production ◽  
Glucose Infusion ◽  
Constant Infusion ◽  
Hepatic Glycogen ◽  
Oral Glucose ◽  
Intravenous Glucose ◽  
Glucose Loading ◽  
Glucose Administration

The amount of glycogen that is formed by gluconeogenetic pathways during glucose loading was quantitated in human subjects. Oral glucose loading was compared with its intravenous administration. Overnight-fasted subjects received a constant infusion or [3-3H]glucose and a marker for gluconeogenesis, [U-14C]lactate or sodium [14C]bicarbonate [14C]bicarbonate). An unlabeled glucose load was then administered. Postabsorptively, or after glucose infusion was terminated, a third tracer ([6-3H]glucose) infusion was initiated along with a three-step glucagon infusion. Without correcting for background stimulation of [14C]glucose production or for dilution of 14C with citric acid cycle carbon in the oxaloacetate pool, the amount of glycogen mobilized by the glucagon infusion that was produced by gluconeogenesis during oral glucose loading was 2.9 +/- 0.7 g calculated from [U-14C]-lactate incorporation and 7.4 +/- 1.3 g calculated using [14C]bicarbonate as a gluconeogenetic marker. During intravenous glucose administration the latter measurement also yielded 7.2 +/- 1.1 g. When the two corrections above are applied, the respective quantities became 5.3 +/- 1.7 g for [U-14C]lactate as tracer and 14.7 +/- 4.3 and 13.9 +/- 3.6 g for oral and intravenous glucose with [14C]bicarbonate as tracer (P less than 0.05, vs. [14C]-lactate as tracer). When [2-14C]acetate was infused, the same amount of label was incorporated into mobilized glycogen regardless of which route of glucose administration was used. Comparison with previous data also suggests that 14CO2 is a potentially useful marker for the gluconeogenetic process in vivo.

scholarly journals Lipoteichoic acid stimulates lipolysis and hepatic triglyceride secretion in rats in vivo.

1995 ◽  
Vol 36 (9) ◽  
pp. 1987-1995
Author(s):  
K Nonogaki ◽  
A H Moser ◽  
X M Pan ◽  
I Staprans ◽  
C Grunfeld ◽  
...  
Keyword(s):  
Lipoteichoic Acid ◽  
Hepatic Triglyceride ◽  
Triglyceride Secretion

Effects of NO-Donors on Thrombus Formation and Microcirculation in Cerebral Vessels of the Rat

1996 ◽  
Vol 76 (01) ◽  
pp. 111-117 ◽  
Author(s):  
Yasuto Sasaki ◽  
Junji Seki ◽  
John C Giddings ◽  
Junichiro Yamamoto
Keyword(s):  
Blood Flow ◽  
Thrombus Formation ◽  
Dependent Manner ◽  
Red Cell ◽  
Cell Velocity ◽  
Red Cell Velocity ◽  
The Mean ◽  
Wall Shear ◽  
Dose Dependent

SummarySodium nitroprusside (SNP) and 3-morpholinosydnonimine (SIN-1), are known to liberate nitric oxide (NO). In this study the effects of SNP and SIN-1 on thrombus formation in rat cerebral arterioles and venules in vivo were assessed using a helium-neon (He-Ne) laser. SNP infused at doses from 10 Μg/kg/h significantly inhibited thrombus formation in a dose dependent manner. This inhibition of thrombus formation was suppressed by methylene blue. SIN-1 at a dose of 100 Μg/kg/h also demonstrated a significant antithrombotic effect. Moreover, treatment with SNP increased vessel diameter in a dose dependent manner and enhanced the mean red cell velocity measured with a fiber-optic laser-Doppler anemometer microscope (FLDAM). Blood flow, calculated from the mean red cell velocity and vessel diameters was increased significantly during infusion. In contrast, mean wall shear rates in the arterioles and venules were not changed by SNP infusion. The results indicated that SNP and SIN-1 possessed potent antithrombotic activities, whilst SNP increased cerebral blood flow without changing wall shear rate. The findings suggest that the NO released by SNP and SIN-1 may be beneficial for the treatment and protection of cerebral infarction

Influence of Platelet Membrane Sialic Acid and Platelet-Associated IgG on Ageing and Sequestration of Blood Platelets in Baboons

1993 ◽  
Vol 70 (04) ◽  
pp. 676-680 ◽  
Author(s):  
H F Kotzé ◽  
V van Wyk ◽  
P N Badenhorst ◽  
A du P Heyns ◽  
J P Roodt ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Life Span ◽  
Blood Platelets ◽  
Senescent Cell ◽  
Platelet Membrane ◽  
Antigen Complex ◽  
The Mean ◽  
Aggregation Of Platelets

SummaryPlatelets were isolated from blood of baboons and treated with neuraminidase to remove platelet membrane sialic acid, a process which artificially ages the platelets. The platelets were then labelled with 111In and their mean life span, in vivo distribution and sites of Sequestration were measured. The effect of removal of sialic acid on the attachment of immunoglobulin to platelets were investigated and related to the Sequestration of the platelets by the spleen, liver, and bone marrow. Removal of sialic acid by neuraminidase did not affect the aggregation of platelets by agonists in vitro, nor their sites of Sequestration. The removal of 0.51 (median, range 0.01 to 2.10) nmol sialic acid/108 platelets shortened their life span by 75 h (median, range 0 to 132) h (n = 19, p <0.001), and there was an exponential correlation between the shortening of the mean platelet life span and the amount of sialic acid removed. The increase in platelet-associated IgG was 0.112 (median, range 0.007 to 0.309) fg/platelet (n = 25, p <0.001) after 0.79 (median, range 0.00 to 6.70) nmol sialic acid/108 platelets was removed (p <0.001). There was an exponential correlation between the shortening of mean platelet life span after the removal of sialic acid and the increase in platelet-associated IgG. The results suggest that platelet membrane sialic acid influences ageing of circulating platelets, and that the loss of sialic acid may have exposed a senescent cell antigen that binds IgG on the platelet membrane. The antibody-antigen complex may then provide a signal to the macrophages that the platelet is old, and can be phagocytosed and destroyed.

STUDIES IN CONGENITAL GENERALIZED LIPODYSTROPHY

1973 ◽  
Vol 72 (3) ◽  
pp. 495-505 ◽  
Author(s):  
Oddmund Søvik ◽  
Svein Oseid
Keyword(s):  
Biological Activity ◽  
Insulin Response ◽  
Epididymal Adipose Tissue ◽  
Large Individual ◽  
Immunoreactive Insulin ◽  
List Type ◽  
Glucose Load ◽  
Congenital Generalized Lipodystrophy ◽  
The One

ABSTRACT The biological activity of plasma insulin from 4 cases of congenital generalized lipodystrophy has been studied, using rat diaphragm and epididymal adipose tissue in vivo. The results are compared with previous data on plasma immunoreactive insulin obtained in these patients. 2 of the 4 cases exhibited unusually high biological insulin activities during the fasting state as well as after an intravenous (iv) glucose load. In the fat pad assay activities as high as 10 000 μU insulin per ml were observed. During childhood the biological insulin activities were generally high, although there were large individual variations. However, in the one case studied after the age of puberty, the insulin response to a glucose load was negligible. Taken together, the biological and immunological activities observed strongly suggest the presence of pancreatic insulin in these patients. It appears that the circulating insulin has a fully biological activity. The decreasing insulin activities after cessation of growth are in agreement with the appearance of frank diabetes at this time.

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