scholarly journals Effect of thyroidectomy on pathways of glucose metabolism in lactating rat mammary gland

1967 ◽  
Vol 105 (2) ◽  
pp. 615-623 ◽  
Author(s):  
Eileen Walters ◽  
Patricia McLean
Keyword(s):  
Mammary Gland ◽  
Glucose Oxidation ◽  
Mammary Tissue ◽  
Control Group ◽  
Phosphogluconate Dehydrogenase ◽  
Lactating Mammary Gland ◽  
Cleavage Enzyme ◽  
Rat Mammary Gland ◽  
Group 3 ◽  
Glucose 6 Phosphate Dehydrogenase

1. Assessment of the overall metabolic changes in lactating mammary gland after thyroidectomy has been made by measurement of the incorporation of 14C from specifically labelled glucose, pyruvate and acetate into 14CO2 and 14C-labelled lipid in the experimental rats and in sham-operated control animals. 2. Thyroidectomy depressed the oxidation of 14C-labelled substrates, an effect still apparent when the control rats were pair-fed with thyroidectomized rats; however, the ratio of oxidation of [1−14C]glucose/oxidation of [6−14C]glucose was unaltered. In parallel with these studies it was revealed that the activities of hexokinase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and NADP-linked isocitrate dehydrogenase were all lower in the thyroidectomized group than in the pair-fed control group. 3. Thyroidectomy also lowered the incorporation of 14C-labelled substrates into 14C-labelled lipid, an effect further studied by measurement of the activities of citrate-cleavage enzyme and acetate thiokinase. Restricting the food intake of the control rats to that of the thyroidectomized group lowered the activity of citrate-cleavage enzyme, but no further depression was observed on thyroidectomy. The oxidized and reduced nicotinamide nucleotide content of mammary tissue was shown to be decreased in the thyroidectomized rats compared with the control rats.

scholarly journals Effect of alloxan-diabetes and treatment with anti-insulin serum on pathways of glucose metabolism in lactating rat mammary gland

1968 ◽  
Vol 109 (3) ◽  
pp. 407-417 ◽  
Author(s):  
Eileen Walters ◽  
Patricia McLean
Keyword(s):  
Mammary Gland ◽  
Glucose Oxidation ◽  
Alloxan Diabetes ◽  
Diabetic Rats ◽  
Control Group ◽  
Tissue Slices ◽  
Phosphogluconate Dehydrogenase ◽  
A Value ◽  
Glucose 6 Phosphate Dehydrogenase

1. The overall metabolic changes in lactating mammary gland in alloxan-diabetic and anti-insulin-serum-treated rats were assessed by measurement of the incorporation of 14C from specifically labelled glucose, pyruvate and acetate into carbon dioxide and lipid, together with measurements of enzymes concerned with the pentose phosphate pathway and with citrate metabolism. 2. Alloxan-diabetes depressed the rate of formation of 14CO2 from [1−14C]glucose and [2−14C]glucose to approx. 10% of the control rate; this was partially reversed by addition of insulin in vitro. The quotient Oxidation of [1−14C]glucose/Oxidation of [6−14C]glucose fell from a value of 17·6 in the control group to 3·9 in the diabetic group and was restored to 14·3 in the presence of insulin in vitro. In keeping with these results it was shown that glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase activities were significantly decreased in alloxan-diabetic rats. 3. Alloxan-diabetes depressed the decarboxylation and the oxidation of labelled pyruvate, but not the oxidation of labelled acetate. 4. The synthesis of lipid from specifically labelled glucose was greatly decreased, that from [2−14C]pyruvate was almost unchanged and that from [1−14C]acetate alone was increased in alloxandiabetic rats. However, the stimulation of lipid synthesis from acetate by glucose was small in the alloxan-diabetic rats compared with the controls. Insulin in vitro partially reversed all these effects. Both citrate-cleavage enzyme and acetate thiokinase activities were decreased in alloxan-diabetic rats. 5. Treatment of rats with anti-insulin serum depressed the formation of 14CO2 from [1−14C]glucose and [2−14C]glucose, but increased that from [6−14C]glucose. This was completely restored by the presence of insulin in vitro. The quotient Oxidation of [1−14C]glucose/Oxidation of [6−14C]glucose fell from a value of 17·6 in the control group to 3·8 in the anti-insulin-serum-treated group. There were no changes in the activity of glucose 6-phosphate dehydrogenase or 6-phosphogluconate dehydrogenase, but the hexokinase distribution changed and the content of the soluble fraction increased significantly. 6. The synthesis of lipid from specifically labelled glucose was depressed in anti-insulin-serum-treated rats; this effect was completely reversed by addition of insulin in vitro to the tissue slices.

CYTOCHROME OXIDASE AND SUCCINIC OXIDASE ACTIVITY IN MAMMARY GLAND MITOCHONDRIA OF LACTATING RATS

1955 ◽  
Vol 33 (1) ◽  
pp. 904-908
Author(s):  
Jules Tuba ◽  
Patricia F. Orr ◽  
G. Stuart Wiberg
Keyword(s):  
Mammary Gland ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Succinic Dehydrogenase ◽  
Female Rats ◽  
Oxidative Enzymes ◽  
Mammary Tissue ◽  
Control Group ◽  
Succinic Dehydrogenase Activity ◽  
Rat Mammary Gland

The effect of lactation on some oxidative enzymes of rat mammary gland mitochondria was examined. Cytochrome oxidase levels were nearly doubled during lactation. Succinic oxidase activity was not demonstrable in breeder female rats four days after the cessation of nursing, or in a control group (non-lactating breeder females, which had weaned their young at least four weeks previously), but during the nursing period considerable activity of the enzyme was observed. Succinic dehydrogenase activity was negligible in mitochondria during involution of rat mammary tissue. On the other hand appreciable anaerobic glycolysis occurred in the resting gland. The greatly increased metabolic activity associated with lactation is reflected in the altered behavior of some of the enzymes of rat mammary gland mitochondria.

Estimations of Rates of Synthesis and Degradation of Several Rat Mammary Gland Enzymes from Changes in Enzyme Activities

1972 ◽  
Vol 50 (4) ◽  
pp. 386-391 ◽  
Author(s):  
G. O. Korsrud ◽  
R. L. Baldwin
Keyword(s):  
Fatty Acid ◽  
Malic Enzyme ◽  
Fatty Acid Synthetase ◽  
Mammary Glands ◽  
Phosphogluconate Dehydrogenase ◽  
Udpglucose Pyrophosphorylase ◽  
Cleavage Enzyme ◽  
Rat Mammary Gland ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Synthesis And Degradation

Based upon rates of decrease in the activities of citrate cleavage enzyme (EC 4.1.3.7), malic enzyme (EC 1.1.1.40), fatty acid synthetase, UDPglucose pyrophosphorylase (EC 2.7.7.9), UDPglucose 4-epimerase (EC 5.1.3.3), and glucose-6-phosphate dehydrogenase (EC 1.1.1.49) in rat mammary glands after adrenalectomy–ovariectomy on the 11th day of lactation, the half-lives of the enzymes were estimated to be 28, 31, 28, 50, 20, and 24 h, respectively. The half-life estimates for UDPglucose pyrophosphorylase and glucose-6-phosphate dehydrogenase compared favorably with previous estimates of 35 and 20 h, respectively, obtained in rats 5 days postpartum utilizing specific immunological techniques. In a second experiment, increases in the activities of enzymes in adrenalectomized, lactating rats after initiation of cortisol therapy were investigated. Rats were adrenalectomized on the 5th day of lactation and cortisol therapy was started 5 days later. The estimated half-lives for citrate cleavage enzyme, malic enzyme, fatty acid synthetase, UDPglucose pyrophosphorylase, UDPglucose 4-epimerase, the A protein of the lactose synthetase complex, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase (EC 1.1.1.44), and hexokinase (EC 2.7.1.1) were, respectively, 84, 60, 92, 76, 170, 102, 79, 88, and 81 h.

CYTOCHROME OXIDASE AND SUCCINIC OXIDASE ACTIVITY IN MAMMARY GLAND MITOCHONDRIA OF LACTATING RATS

1955 ◽  
Vol 33 (6) ◽  
pp. 904-908 ◽  
Author(s):  
Jules Tuba ◽  
Patricia F. Orr ◽  
G. Stuart Wiberg
Keyword(s):  
Mammary Gland ◽  
Cytochrome Oxidase ◽  
Oxidase Activity ◽  
Succinic Dehydrogenase ◽  
Female Rats ◽  
Oxidative Enzymes ◽  
Mammary Tissue ◽  
Control Group ◽  
Succinic Dehydrogenase Activity ◽  
Rat Mammary Gland

The effect of lactation on some oxidative enzymes of rat mammary gland mitochondria was examined. Cytochrome oxidase levels were nearly doubled during lactation. Succinic oxidase activity was not demonstrable in breeder female rats four days after the cessation of nursing, or in a control group (non-lactating breeder females, which had weaned their young at least four weeks previously), but during the nursing period considerable activity of the enzyme was observed. Succinic dehydrogenase activity was negligible in mitochondria during involution of rat mammary tissue. On the other hand appreciable anaerobic glycolysis occurred in the resting gland. The greatly increased metabolic activity associated with lactation is reflected in the altered behavior of some of the enzymes of rat mammary gland mitochondria.

scholarly journals Rat mammary-gland fatty acid synthase. A simple purification procedure and stoicheiometry of CoA ester binding

1982 ◽  
Vol 203 (1) ◽  
pp. 45-50 ◽  
Author(s):  
P M Ahmad ◽  
D S Feltman ◽  
F Ahmad
Keyword(s):  
Mammary Gland ◽  
Fatty Acid ◽  
Fatty Acid Synthase ◽  
Specific Activity ◽  
Simple Procedure ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Performic Acid ◽  
Mammary Tissue ◽  
Rat Mammary Gland

A simple procedure was devised which allows purification of rat lactating-mammary-gland fatty acid synthase to a high degree of purity, with recoveries of activity exceeding 50%. Over 50 mg of enzyme was isolated from 60 g of mammary tissue. The specific activity of the purified enzyme was about 2.5 mumol of NADPH oxidized/min per mg of protein at 37 degrees. The enzyme appeared homogeneous by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and by immunodiffusion analysis. Each mol (Mr 480 000) of the enzyme bound 3 mol of acetyl and 3-4 mol of malonyl groups when the binding experiments were performed at 0 degrees for 30 s. The presence of NADPH did not influence the binding stoicheiometry for these acyl-CoA derivatives. Approx. 2 mol of taurine was found per mol of the performic acid-oxidized enzyme, suggesting that there were 2 mol of 4′-phosphopantetheine in the native enzyme. Rat mammary-gland fatty acid synthase required free CoA for activity.

scholarly journals Control of glucose metabolism in isolated acini of the lactating mammary gland of the rat. The ability of glycerol to mimic some of the effects of insulin

1977 ◽  
Vol 168 (3) ◽  
pp. 465-474 ◽  
Author(s):  
A M Robinson ◽  
D H Williamson
Keyword(s):  
Mammary Gland ◽  
Glucose Metabolism ◽  
Glucose Uptake ◽  
Glucose Utilization ◽  
Homogeneous Population ◽  
Furoic Acid ◽  
Lactating Mammary Gland ◽  
Rat Mammary Gland ◽  
Pyruvate Ratio

Inhibition of glucose uptake by acetoacetate and relief of this inhibition by insulin found previously in slices of rat mammary gland [Williamson, McKeown & Ilic (1975) Biochem. J. 150. 145-152] was confirmed in acini, which represent a more homogeneous population of cells. Glycerol (1mM) behaved like insulin (50 minuits/ml) in its ability to relieve the inhibition of glucose (5 mM) utilization caused by acetoacetate (2 mM) in acini. Both glycerol and insulin reversed the increase in [citrate] and the decrease in [glycerol 3-phosphate] and the [lactate]/[pyruvate] ratio in the presence of acetoacetate. Lipogenesis from 3H2O, [3-14C] acetoacetate, [1-14C]- and [6-14C]-glucose was stimulated, whereas 14CO2 formation from [3-14C]acetoacetate was decreased. Neither insulin nor glycerol relieved the acetoacetate inhibition of glucose uptake when lipogenesis was inhibited by 5-(tetradecyloxy)-2-furoic acid. From measurements of [3-14C]acetoacetate incorporation into lipid in the various situations it is suggested that a cytosolic pathway for acetoacetate utilization may exist in rat mammary gland. In the absence of acetoacetate, glycerol inhibited glucose utilization by 60% and increased both [glycerol 3-phosphate] and the [lactate/[pyruvate] ratio. Possible ways in which glycerol may mimic the effects of insulin are discussed.

scholarly journals The influence of Theranekron® on glucose-6-phosphate dehydrogenase activity in rat ovaries, intact and with ischemia-reperfusion injury

2021 ◽  
Vol 91 (1) ◽  
pp. 81-88
Author(s):  
Tolunay Kozlu ◽  
◽  
Fatma Güler ◽  
Pınar Peker Akalın ◽  
Filiz Kazak ◽  
...  
Keyword(s):  
Reperfusion Injury ◽  
Dehydrogenase Activity ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Control Group ◽  
Group 4 ◽  
Group 3 ◽  
Group 2 ◽  
Glucose 6 Phosphate Dehydrogenase

The effect of Theranekron® on rat ovaries was evaluated in healthy and ischemia-reperfusion injury models. The rats were divided into four groups: group 1: control, group 2: Theranekron® (single dose of 0.3 mg/kg intraperitoneally), group 3: torsion + detorsion, and group 4: torsion + detorsion + Theranekron® (single dose 0,3 mg/kg, intraperitoneally). The ovaries were homogenized by sonication before the analysis and supernatant glucose-6-phosphate dehydrogenase activity, reduced nicotinamide adenine dinucleotide phosphate, reduced glutathione and total protein levels were evaluated spectrophotometrically. Ovary tissues were histologically examined. In group 2, glucose-6-phosphate dehydrogenase activity was significantly reduced (P<0.01) compared to the control group and an increased number of atretic follicles, and hyperaemic and haemorrhagic regions were seen histologically; in group 3, although glucose-6-phosphate dehydrogenase activity was not changed, intense hyperaemia and hemorrhage was observed in the veins of the medulla region and in the cortex. Group 4 showed a decrease in glucose-6-phosphate dehydrogenase activity compared to the control group (P<0.01). Histologically, when compared to group 3, group 4 showed fewer atretic follicles and decreased hyperaemia and hemorrhage in the ovaries, excluding the medulla region. There were no significant differences regarding reduced glutathione and reduced nicotinamide adenine dinucleotide phosphate levels between the groups. The Theranekron® dose applied had some negative effects, such as reduced glucose-6-phosphate dehydrogenase activity, an increased number of atretic follicles, and hyperemia in the corpus luteum and medulla region in intact rat ovaries. Although it reduced glucose-6-phosphate dehydrogenase activity, Theranekron® may have had slight remedial effects on rat ovaries with ischemia-reperfusion injury.

scholarly journals ADDITIVE EFFECT OF GENES POLYMORPHISM OF FOLATE CYCLE PROTEINS AND HOMOCYSTEIN LEVEL IN PATIENTS WITH PROLIFERATIVE DISEASES OF THE BREAST AS A POTENTIAL FACTOR OF THE RISK OF THROMBOSSES

2018 ◽  
pp. 46-53
Author(s):  
Aleksandr V. Markovsky
Keyword(s):  
Breast Cancer ◽  
Mammary Gland ◽  
Molecular Genetic ◽  
Additive Effect ◽  
Tissue Homogenate ◽  
Breast Diseases ◽  
Mammary Tissue ◽  
Control Group ◽  
Homocysteine Concentration ◽  
Serum Homocysteine

Aim.The aim of study was to examine the relationship between serum and mammary gland homocysteine levels with the carrier of separate SNP (single nucleotide polymorphism) genes of the folate metabolism system in patients with proliferative diseases and breast cancer.Methods and results.The study included 182 patients with proliferative diseases of the mammary gland in transbaikalia. The control group included 144 women who did not have oncological diseases. The serum homocysteine level and the supernatant of the mammary tissue homogenate were evaluated by high performance liquid chromatography. Genotyping for the detection of polymorphism MTHFRС677T, MTHFRА1298C, MTRA2756G, MTRRA66G was carried out by polymerase chain reaction with the detection of the amplification product in real time. In the course of molecular genetic testing in patients with proliferative diseases of the mammary gland, there was found: 1) the absence of an explicit association of the carriage of genetic polymorphism MTHFRС677T, MTHFRА1298C, MTRA2756G and MTRRA66G with serum homocysteine concentration, however, comparative hyperhomocysteinemia and, to a lesser extent, in women with the benign breast diseases; 2) the highest homocysteine content in the blood in patients with breast cancer whose genotype was characterized by combinations of polymorphic alleles MTR2756G x MTRR66G; 3) that the MTR2756A allele and genotype MTHFR1298AC, especially their combination of MTHFR1298AC x MTR2756A, increase the risk of developing benign breast formations; 4) the effect of the risk alleles MTR2756G and MTRR66GON the concentration of homocystein in the tumor tissue of the mammary gland.Conclusion. These patterns indicate a certain contribution of the polymorphisms studied, especially their additive effect, both in the development of proliferative diseases of the mammary gland and in the possible potentiation of prothrombotic effects in these patients against the background of tumor progression and homocysteine metabolism disorders.

THE INFLUENCE OF ADRENALECTOMY UPON THE ACTIVITY OF THE HEXOSEMONOPHOSPHATE SHUNT IN THE LIVERS AND MAMMARY GLANDS OF LACTATING RATS

1960 ◽  
Vol 38 (1) ◽  
pp. 1265-1273 ◽  
Author(s):  
J. S. Willmer
Keyword(s):  
Enzyme Activity ◽  
Considerable Increase ◽  
Mammary Glands ◽  
Mammary Tissue ◽  
Hepatic Tissue ◽  
Phosphogluconate Dehydrogenase ◽  
Growth Changes ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Adrenalectomized Rats ◽  
Hepatic Level

The development of the hexosemonophosphate shunt in mammary tissue and liver of lactating rats has been studied. A sixfold increase in mammary glucose-6-phosphate dehydrogenase levels between parturition and weaning was accompanied by a considerable increase in 6-phosphogluconate dehydrogenase activity. The hepatic level of the former enzyme was also elevated 11-fold during this period. Adrenalectomy at parturition, or on the 3rd, 6th, 9th, or 14th days of lactation, depressed the activity of this pathway in mammary gland, a lowered level being observed in all cases after operation. A slight increase in enzyme activity was found in hepatic tissue in the immediate postoperative period; this was succeeded by a decrease.These results are discussed in relation to the growth changes observed in groups of unoperated and adrenalectomized rats.

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