The Effect of Starvation and Diabetes on Glycolytic Enzymes in Human Adipose Tissue

1971 ◽  
Vol 41 (6) ◽  
pp. 545-553 ◽  
Author(s):  
D. J. Galton ◽  
J. P. D. Wilson

1. The activities of hexokinase (EC 2.7.1.1) and phosphofructokinase (EC 2.7.1.11) have been studied in homogenates of adipose tissue taken from human diabetics, fasting and control patients. 2. Three isoenzymes of hexokinase were observed with apparent Km values for glucose of 1.04 × 10-5 m, 2.6 × 10-4 m and 2.9 × 10-4 m, respectively. 3. No change in activity of hexokinase was found in adipose tissue of untreated diabetics (n = 22), treated diabetics (n = 13) or non-diabetic controls. However, fasting was associated with a decrease of approx. 40% in the activity of hexokinase in adipose tissue. 4. In contrast, there was a marked decrease in the activity of phosphofructokinase in adipose tissue from untreated diabetics (n = 24) which was restored to normal by either insulin therapy or treatment by hypoglycaemic drugs. 5. There was a negative correlation between the phosphofructokinase/hexokinase ratio in adipose tissue and the fasting blood glucose (P = 0.01) and the 2 h blood glucose (P = 0.03) after an oral glucose load (50 g). 6. The functional significance of the changes in enzyme activities is discussed in relation to the glucose intolerance of diabetes.

2020 ◽  
Vol 6 (4) ◽  
pp. 432-438
Author(s):  
EO Taiwo ◽  
LO Thanni

Background: Studying post-prandial fluctuations in blood glucose has high physiological and clinical relevance. Physical exercise is known to influence this fluctuation. Objectives: To determine the gender difference in glucose tolerance following physical exercise in a population of university students. Methods: A total of 146 students were randomly selected from the Olabisi Onabanjo University, Sagamu, Ogun State, southwest Nigeria. Following overnight fast, Oral Glucose Tolerance Test (OGTT) was carried out. Pre-exercise, fasting blood glucose (FBG) was measured at 0 mins, and after oral glucose load of 75 grams at 30 minutes intervals for 2 hours. The physical exercise involved cycling using a bicycle ergometer for an hour. Thereafter, OGTT was conducted again 1 hour post-exercise. Results: The ages of the subjects ranged from 20 years to 49 years. There were 73 (50.0%) females. The mean Body Mass Index (BMI) of 23.5±1.1 kg/m2 for females was comparable to 22.8±0.3 kg/m2 for the males (p = 0.571). Seven (9.6%) females were obese compared to 2 (2.7%) males. The mean post-prandial blood glucose increased from 71.6±1.6 mg/dl to 90.8±1.8 mg/dl after oral glucose load and thereafter to 88.0±4.2 mg/dl at 120 minutes among males. The post-exercise blood glucose patterns included a significant reduction in the mean FBS for males compared to females (64.5±1.9 mg/dl vs. 71.7±1.9 mg/dl; p = 0.001) Conclusions: Glucose tolerance with exercise is better in females than males. The clinical importance of physical exercise lies in its effect on glucose tolerance.


Author(s):  
Rahel Catherina Loeliger ◽  
Claudia Irene Maushart ◽  
Gani Gashi ◽  
Jaël Rut Senn ◽  
Martina Felder ◽  
...  

Objective Human brown adipose tissue (BAT) is a thermogenic tissue activated by the sympathetic nervous system in response to cold. It contributes to energy expenditure (EE) and takes up glucose and lipids from the circulation. Studies in rodents suggest that BAT contributes to the transient rise in EE after food intake, so called diet-induced thermogenesis (DIT). We investigated the relationship between human BAT activity and DIT in response to glucose intake in 17 healthy volunteers. Methods We assessed DIT, cold induced thermogenesis (CIT) and maximum BAT activity at three separate study visits within two weeks. DIT was measured by indirect calorimetry during an oral glucose tolerance-test. CIT was assessed as the difference in EE after cold exposure of two hours duration as compared to warm conditions. Maximal activity of BAT was assessed by 18F-FDG-PET/MRI after cold exposure and concomitant pharmacological stimulation with Mirabegron. Results 17 healthy men (mean age 23.4 years, mean BMI 23.2 kg/m2) participated in the study. EE increased from 1908 (±181) kcal/24 hours to 2128 (±277) kcal/24 hours (p<0.0001, +11.5%) after mild cold exposure. An oral glucose load increased EE from 1911 (±165) kcal/24 hours to 2096 (±167) kcal/24 hours at 60 minutes (p<0.0001, +9.7%). The increase in EE in response to cold was significantly associated with BAT activity (R2=0.43, p=0.004). However, DIT was not associated with BAT activity (R2=0.015, p=0.64). Conclusion DIT after an oral glucose load was not associated with stimulated 18F-FDG uptake into BAT suggesting that DIT is independent from BAT activity in humans.


1975 ◽  
Vol 49 (1) ◽  
pp. 27-32
Author(s):  
M. A. Page ◽  
D. J. Galton

1. Glucose 6-phosphate, fructose 6-phosphate, fructose diphosphate, glycerol phosphate and uridine diphosphate glucose have been measured in human adipose tissue and blood from obese subjects under fed and fasting conditions and in obese diabetic and non-diabetic subjects before and after an oral glucose load (100 g). 2. Adipose tissue metabolites expressed as nmol/g wet weight correlated inversely with adipocyte diameter. 3. After fasting, fructose diphosphate and glycerol phosphate in adipose tissue decreased significantly. 4. The basal concentrations of metabolites in blood and adipose tissue were maintained at similar concentrations in diabetic and non-diabetic subjects despite very different blood glucose concentrations. 5. The significant increase in adipose tissue glucose 6-phosphate after the glucose load seen in the non-diabetic but not in the diabetic subjects suggests that glucose uptake is decreased in the diabetic adipocyte.


1981 ◽  
Vol 1 (6) ◽  
pp. 469-476 ◽  
Author(s):  
Mary C. Sugden ◽  
David L. Watts ◽  
Christopher E. Marshall

Lipogenesis in livers of fed but not of starved rats is increased after intragastric feeding with glucose. In contrast, lipogenesis in brown adipose tissue increases in both fed and starved animals. These observations suggest that lipogenesis in brown adipose tissue is regulated by mechanisms in addition to, or other than, those operating in liver. The fate of newly synthesized lipid in brown adipose tissue is not known. However, the formation of palmitoyl-carnitine from palmitoyl-CoA and carnitine by mitochondria from brown fat was inhibited by malonyl-CoA. Although inhibition was not 100%, it is implied that mitochondrial uptake of the newly synthesized fat by the carnitine acyltransferase system is restricted under conditions of increased lipogenesis.


2012 ◽  
Vol 1 (2) ◽  
Author(s):  
Ellyza Nasrul ◽  
Sofitri Sofitri

AbstrakAsam urat (AU) merupakan produk akhir dari katabolisme adenin dan guanin yang berasal dari pemecahannukleotida purin. Urat dihasilkan oleh sel yang mengandung xanthine oxidase, terutama hepar dan usus kecil.Hiperurisemia adalah keadaan kadar asam urat dalam darah lebih dari 7,0 mg/dL.Pra diabetes adalah subjek yangmempunyai kadar glukosa plasma meningkat akan tetapi peningkatannya masih belum mencapai nilai minimaluntuk kriteria diagnosis diabetes melitus (DM). Glukosa darah puasa terganggu merupakan keadaan dimanapeningkatan kadar FPG≥100 mg/dL dan <126 mg/dL. Toleransi glukosa terganggu merupakan peningkatanglukosa plasma 2 jam setelah pembebanan 75 gram glukosa oral (≥140 mg/dL dan <200mg/dL) dengan FPG<126 mg/dL.Insulin juga berperan dalam meningkatkan reabsorpsi asam urat di tubuli proksimal ginjal. Sehinggapada keadaan hiperinsulinemia pada pra diabetes terjadi peningkatan reabsorpsi yang akan menyebabkanhiperurisemia. Transporter urat yang berada di membran apikal tubuli renal dikenal sebagai URAT-1 berperandalam reabsorpsi urat.Kata kunci: Hiperurisemia, Pra DiabetesAbstractUric acid (AU) is the end product of the catabolism of adenine and guanine nucleotides derived from thebreakdown of purines. Veins produced by cells containing xanthine oxidase, especially the liver and small intestine.Hyperuricemia is a state in the blood uric acid levels over 7.0 mg / dL.Pre-diabetes is a subject which has a plasmaglucose level will rise but the increase is still not reached the minimum value for the diagnostic criteria for diabetesmellitus (DM). Impaired fasting blood glucose is a condition in which increased levels of FPG ≥ 100 mg / dL and<126 mg / dL. Impaired glucose tolerance is an increase in plasma glucose 2 hours after 75 gram oral glucose load(≥ 140 mg / dL and <200mg/dl) with FPG <126 mg / dL.Insulin also plays a role in increasing the reabsorption ofuric acid in renal proximal tubule. So that the hyperinsulinemia in the pre-diabetic condition increases thereabsorption of which will lead to hyperuricemia. Urate transporter in the apical membrane of renal tubule known asURAT-1 plays a role in urate reabsorption.Keywords: Hyperuricemia, Pre-diabetes


2000 ◽  
Vol 84 (1) ◽  
pp. 19-23 ◽  
Author(s):  
P. J. Wood ◽  
M. U. Beer ◽  
G. Butler

Data from clinical studies established that there was an inverse linear relationship between measures of postprandial blood glucose and insulin responses to an oral glucose load, consumed in a drink, and the logarithm of viscosity of the drink. These data have been re-analysed using concentration and molecular weight as the dependent variables. Molecular weight (M) of the β-glucans used was determined using high-performance size exclusion chromatography equipped with a triple detector system of right angle light scattering, viscometry and refractive index. A significant relationship between changes in peak blood glucose and a combination of logarithm of the concentration and logarithm of M was found.


1987 ◽  
Vol 253 (2) ◽  
pp. H276-H282
Author(s):  
K. H. McDonough ◽  
R. W. Barbee ◽  
C. Dobrescu ◽  
C. H. Lang ◽  
J. J. Spitzer

The aim of this study was to determine whether diabetes enhanced the sensitivity of the myocardium to the deleterious effects of in vivo-administered Escherichia coli. Diabetes was induced in two groups of animals. One group received 70 mg/kg streptozotocin (iv) and exhibited a severe diabetes with elevated fasting and fed blood glucose concentrations and a markedly abnormal response to an oral glucose load. The second group received 45 mg/kg streptozotocin, was mildly diabetic (termed “latent” diabetes), and was characterized by normal fasting blood glucose but slightly elevated fed blood glucose and an abnormal response to a glucose load. A third group of rats received vehicle and served as time-matched control animals. Four weeks after induction of diabetes, all animals were catheterized under ether anesthesia and some received intraperitoneal injections of live E. coli. In vitro myocardial performance was assessed using the isolated, perfused working heart preparation. Ventricular function curves were generated by changing left atrial filling pressure and measuring changes in heart rate, cardiac output, and aortic peak systolic pressure. Cardiac performance in the severe diabetic group was depressed at the highest preload but was unchanged at lower preloads. Function in the latent diabetic group was not different from control. Sepsis induced a slight decrease in cardiac performance in the control group and resulted in larger reductions in the latent and severe diabetic groups. A depression in aortic flow was the major consequence of sepsis in the latent diabetic group, whereas decreased coronary flow was the primary change in the severe diabetic group.(ABSTRACT TRUNCATED AT 250 WORDS)


1981 ◽  
Vol 139 (6) ◽  
pp. 485-493 ◽  
Author(s):  
R. B. Tattersall

A raised blood sugar level no more defines a single entity than does a raised bilirubin or a low haemoglobin. Diabetes is a heterogenous group of disorders whose only common factor is hyperglycaemia (Tattersallet al, 1980). The classification of diabetes is being revised, although the changes are of more relevance to epidemiologists than clinicians. Previous standards of normal glucose tolerance were set too low, so that some people were labelled diabetic who had no symptoms and have proved on follow-up not to be at risk of developing complications such as retinopathy (i.e. they had a non-disease). Epidemiological evidence suggests that the cut-off point for ‘true’ diabetes (i.e. a condition which leads to complications and shortening of life span) is a blood glucose level two hours after a 50 G oral glucose load of 11.1 mMol/L (National Diabetes Data Group, 1979). This corresponds to a fasting blood glucose level of 7 mMol/L or below. Hence, a single blood glucose value, either in the fasting state or two hours after a 50 G glucose load, is enough to diagnose diabetes and glucose tolerance tests should hardly ever be necessary.


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