Regulation of placental metabolism by glucose supply

1995 ◽  
Vol 7 (3) ◽  
pp. 365 ◽  
Author(s):  
WW Hay
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Glucose Consumption ◽  
Maternal Plasma ◽  
Plasma Glucose Concentration ◽  
Transporter Proteins ◽  
Fetal Plasma ◽  
Carbon Substrates ◽  
Glucose Supply

Glucose is supplied to the placenta and fetus from the maternal plasma according to concentration-dependent mechanisms exhibiting saturation kinetics that are mediated by facilitative transporter proteins on both the maternal-facing microvillus and fetal-facing basal trophoblast membranes. Placental glucose transport to the fetus requires a net maternal-to-fetal plasma glucose concentration gradient that is determined by placental as well as fetal glucose consumption. Fetal plasma glucose concentration, independent of maternal glucose concentration, regulates the partition of placental glucose uptake into transfer to the fetus and consumption by the placenta. Placental transport capacity increases with advancing gestation, probably by an increased number of transporter proteins as surface area increases. Placental glucose consumption contributes to most or all of placental lactate and fructose production and other less well defined non-oxidative pathways of carbon metabolism. Placental glucose consumption accounts for at least 50% of placental oxygen consumption which remains independent of short-term or long-term changes in placental glucose supply, thus requiring varying amounts of other carbon substrates. Placental glucose supply, therefore, plays a key role in regulating placental glucose metabolism and placental carbon balance, and interacts reciprocally with other carbon substrates to maintain placental oxidative metabolism.

scholarly journals Effect of Pericampylus glaucus on plasma glucose concentration and lipid profile in streptozotocin-induced diabetic rats

2016 ◽  
Vol 11 (1) ◽  
pp. 200 ◽  
Author(s):  
Muhammad Kifayatullah ◽  
Pinaki Sengupta
Keyword(s):  
Lipid Profile ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Ethanolic Extract ◽  
Diabetic Rats ◽  
Plasma Glucose Concentration ◽  
Short And Long Term ◽  
Different Doses ◽  
Long Term Studies

<p class="Abstract">The purpose of this study was to evaluate the effects of <em>Pericampylus glaucus</em> extract on plasma glucose concentration and lipid profile in normal and streptozotocin-induced diabetic rats. The ethanolic extract were administered orally at three different doses (400, 600 and 800 mg/kg) and glibenclamide (20 mg/kg p.o.) for 21 days after 72 hours of streptozotocin injection. During the short- and long-term studies, the extract was found to possess significant (p&lt;0.01, p&lt;0.001) anti-diabetic activity in normal and diabetic rats compared with untreated normal and untreated diabetic group. It also caused reduction in the level of total cholesterol, triglyceride, and LDL etc. and improvement in the HDL level compared with untreated diabetic rats. Reduction in the fasting blood sugar, cholesterol, triglyceride, urea, LDL, creatinine levels and improvement in the HDL by<em> P. glaucus</em> indicates that plant has anti-diabetic activity along with anti hyperlipidemic efficacy and provides a scientific rationale for the use.</p><p> </p>

scholarly journals NMR Determination of Intracerebral Glucose Concentration and Transport Kinetics in Rat Brain

1992 ◽  
Vol 12 (3) ◽  
pp. 448-455 ◽  
Author(s):  
Graeme F. Mason ◽  
Kevin L. Behar ◽  
Douglas L. Rothman ◽  
Robert G. Shulman
Keyword(s):  
Steady State ◽  
Plasma Glucose ◽  
Glucose Concentration ◽  
Goodness Of Fit ◽  
Glucose Consumption ◽  
Plasma Glucose Concentration ◽  
Transport Parameters ◽  
Glucose Levels ◽  
Normal Glucose ◽  
Wet Weight

The concentration of intracerebral glucose as a function of plasma glucose concentration was measured in rats by 13C NMR spectroscopy. Measurements were made in 20–60 min periods during the infusion of [1-13C]d-glucose, when intracerebral and plasma glucose levels were at steady state. Intracerebral glucose was found to vary from 0.7 to 19 μmol g−1 wet weight as the steady-state plasma glucose concentration was varied from 3 to 62 m M. A symmetric Michaelis–Menten model was fit to the brain and plasma glucose data with and without an unsaturable component, yielding the transport parameters Km, Vmax, and Kd. If it is assumed that all transport is saturable ( Kd = 0), then Km = 13.9 ± 2.7 m M and Vmax/ Vgly = 5.8 ± 0.8, where Vgly is the rate of brain glucose consumption. If an unsaturable component of transport is included, the transport parameters are Km = 9.2 ± 4.7 m M, Vmax/ Vgly = 5.3 ± 1.5, and Kd/ Vgly = 0.0088 ± 0.0075 ml μmol−1. It was not possible to distinguish between the cases of Kd = 0 and Kd > 0, because the goodness of fit was similar for both. However, the results in both cases indicate that the unidirectional rate of glucose influx exceeds the glycolytic rate in the basal state by 2.4-fold and as a result should not be rate limiting for normal glucose utilization.

Lack of relationship between opioid-induced changes in fetal breathing and plasma glucose levels

1995 ◽  
Vol 269 (3) ◽  
pp. R702-R707
Author(s):  
H. H. Szeto ◽  
P. Y. Cheng ◽  
Y. Soong ◽  
D. L. Wu
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Plasma Glucose Concentration ◽  
Glucose Regulation ◽  
Fetal Sheep ◽  
Receptor Selectivity ◽  
Fetal Plasma ◽  
Glucose Levels ◽  
Fetal Breathing ◽  
Induced Changes

The mechanisms by which opioids increase or decrease fetal breathing remain unclear. Fetal plasma glucose is known to modulate breathing activity, and opioids have been reported to alter glucose regulation in the adult. In this study, we investigated whether alterations in fetal breathing by opioids may be explained by changes in plasma glucose levels. We compared the effects of morphine (nonselective), [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin (DAMGO, mu-selective), and [D-Pen2,D-Pen5]enkephalin (DPDPE, delta-selective) on fetal breathing and plasma glucose in unanesthetized fetal sheep. Whereas morphine at 1.2 and 5.0 mg/h iv resulted in an increase in breath number (P < 0.01), plasma glucose was decreased after 1.2 mg/h (P = 0.006) but increased after 5.0 mg/h (P = 0.008). DAMGO (100 micrograms/h icv) increased plasma glucose (P = 0.001) but reduced fetal breathing (P < 0.001). In contrast, DPDPE (30 micrograms/h icv) increased fetal breathing (P = 0.026) but had no effect on plasma glucose concentration. These data demonstrate that the actions of opioids on fetal glucose regulation and breathing are dependent on dose and receptor selectivity. However, there is no relationship between the effects of opioids on fetal breathing and plasma glucose concentration.

scholarly journals Long-term Management of Plasma Glucose Concentration by a Single Administration of Streptozocin in a Dog with Insulinoma

2007 ◽  
Vol 60 (12) ◽  
pp. 867-871
Author(s):  
Masashi YUKI ◽  
Kiyomi SUZUKI ◽  
Sakiko TANAHASHI ◽  
Mayuko KATOH ◽  
Takashi HIRANO ◽  
...  
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Plasma Glucose Concentration ◽  
Single Administration ◽  
Term Management

scholarly journals Direct Chemical Measurement of the λ of the Lumped Constant of the [14C]Deoxyglucose Method in Rat Brain: Effects of Arterial Plasma Glucose Level on the Distribution Spaces of [14C]Deoxyglucose and Glucose and on λ

1989 ◽  
Vol 9 (3) ◽  
pp. 304-314 ◽  
Author(s):  
Kentaro Mori ◽  
Nancy Cruz ◽  
Gerald Dienel ◽  
Thomas Nelson ◽  
Louis Sokoloff
Keyword(s):  
Plasma Glucose ◽  
Glucose Concentration ◽  
Severe Hypoglycemia ◽  
Plasma Glucose Concentration ◽  
Operational Equation ◽  
Chemical Measurements ◽  
Lumped Constant ◽  
Dg Method ◽  
Arterial Plasma ◽  
Distribution Spaces

The lumped constant in the operational equation of the 2-[14C]deoxyglucose (DG) method contains the factor λ that represents the ratio of the steady-state tissue distribution spaces for [14C]DG and glucose. The lumped constant has been shown to vary with arterial plasma glucose concentration. Predictions based mainly on theoretical grounds have suggested that disproportionate changes in the distribution spaces for [14C]DG and glucose and in the value of λ are responsible for these variations in the lumped constant. The influence of arterial plasma glucose concentration on the distribution spaces for DG and glucose and on λ were, therefore, determined in the present studies by direct chemical measurements. The brain was maintained in steady states of delivery and metabolism of DG and glucose by programmed intravenous infusions of both hexoses designed to produce and maintain constant arterial concentrations. Hexose concentrations were assayed in acid extracts of arterial plasma and freeze-blown brain. Graded hyperglycemia up to 28 m M produced progressive decreases in the distribution spaces of both hexoses from their normoglycemic values (e.g., ∼ – 20% for glucose and – 50% for DG at 28 m M). In contrast, graded hypoglycemia progressively reduced the distribution space for glucose and increased the space for [14C]DG. The values for λ were comparatively stable in normoglycemic and hyperglycemic conditions but rose sharply (e.g., as much as 9–10-fold at 2 m M) in severe hypoglycemia.

scholarly journals Comparative Study of Fasting Plasma Glucose Concentration and Glucose Challenge Test for Screening Gestational Diabetes Mellitus

2014 ◽  
Vol 6 (2) ◽  
pp. 75-78
Author(s):  
Sujaya Sham ◽  
B Poornima R Bhat ◽  
Aruna Kamath
Keyword(s):  
Diabetes Mellitus ◽  
Plasma Glucose ◽  
Fasting Plasma Glucose ◽  
Glucose Concentration ◽  
Challenge Test ◽  
Plasma Glucose Concentration ◽  
Fasting Plasma ◽  
Glucose Challenge Test ◽  
Glucose Challenge ◽  
Fasting Plasma Glucose Concentration

ABSTRACT Background To compare the sensitivity and specificity of fasting plasma glucose (FPG) with that of standard glucose challenge test (GCT). Materials and methods Eighty-nine eligible pregnant women underwent GCT between 24th and 28th gestational week, followed by a diagnostic 3 hours 100 gm oral glucose tolerance test within 1 week. Out patient clinic in Father Muller Medical College Hospital, Mangalore. Data was analyzed for significance by chi-square test. Results Fasting plasma glucose concentration at a threshold value of 90 mg/dl and GCT at recommended standard threshold of 140 mg/dl yielded sensitivities of 66.7% and 100% respectively and specificities of 87.3% and 46.5% respectively. Reducing the threshold value of FPG to 80 mg/dl increased the sensitivity of test to 91.7% with specificity of 54.9% which was comparable to standard GCT, in our study. Conclusion Measuring FPG concentration using a cut-off of. 80 mg/dl is an easier, tolerable and more cost effective procedure than GCT for detecting more severe cases of GDM, i.e. the diabetes mellitus group. In resource poor settings with population belonging to average risk or high risk category, FPG at a cut-off of 90 mg/dl can be used to screen GDM. How to cite this article Sham S, Bhat BPR, Kamath A. Comparative Study of Fasting Plasma Glucose Concentration and Glucose Challenge Test for Screening Gestational Diabetes Mellitus. J South Asian Feder Obst Gynae 2014;6(2):75-78.

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