Blood glucose and the liver

Cahill, George F.; Ashmore, James; Renold, Albert E.; Hastings, A. Baird

doi:10.1016/0002-9343(59)90316-x

Cited by 263 publications

(59 citation statements)

References 134 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The present glucose effects are consistent with the findings: (1) that intravenous glucose in intact mice activates glycogen synthetase by a mechanism independent of insulin secretion,7' 20 and (2), that glucose inactivates phosphorylase in the rat diaphragm.8 The observation of Holmes and Mansour2l that glucose activates phosphorylase phosphatase is of great interest and analogous activations may underlie the present enzyme interconversions. It would seem unlikely that a reduction in the tissue level of cyclic AMP is involved.…”

supporting

confidence: 89%

Effects of Glucose on Glycogen Synthetase, Phosphorylase, and Glycogen Deposition in the Perfused Rat Liver

Buschiazzo

Exton

Park

1970

Proc. Natl. Acad. Sci. U.S.A.

102

View full text Add to dashboard Cite

Abstract. An increase in the perfusate glucose concentration from near zero to about 11 mM increased glycogen synthesis in the perfused, isolated rat liver from zero to a value about half the maximum seen in the intact animal. Increased synthesis appeared to be due not only to provision of substrate but also to conversion of glycogen synthetase to the active form and of glycogen phosphorylase to the inactive form. These glucose effects, which are apparently independent of changes in levels of hormones or adenosine 3':5'-cyclic phosphate, may be physiologically significant for control of the blood glucose level.The liver plays a central role in the regulation of blood glucose.1' 2 Control appears to be due in part to changes in the tissue level of adenosine 3': 5'-cyclic phosphate (cyclic AMP) resulting from alterations in the activity of the sympathetic nervous system and in the secretion of glucagon and insulin.3 In addition, the liver possesses intrinsic control systems2' 4 which help stabilize the blood glucose. One of these is described in this report.There are several possibilities regarding the nature of these nonhormonal controls. A negative feedback system in which a rise in blood glucose suppresses gluconeogenesis has been proposed by Ruderman and Herrera5 but these workers could show only a small suppression (25%) of gluconeogenesis from alanine by 17 mM glucose in the isolated, perfused liver, and Exton and Park6 could not show any inhibition of gluconeogenesis from lactate by 19 mM glucose in a similar system. A quantitatively significant regulation of glucose utilization through adjustments in the rate of hepatic glycolysis also seems unlikely since the intrinsic rate of this process is very low under aerobic conditions.6 Another possibility, which we have examined in this study, is that glycogen metabolism is affected by the glucose concentration. In this connection, DeWulf and Hers7 found that intravenous injection of glucose into the mouse led to a rapid activation of hepatic glycogen synthetase and suggested that this effect was independent of changes in insulin or glucocorticoid secretion. Holmes and Mansour8 reported that glucose inactivated glycogen phosphorylase in the isolated rat diaphragm in vitro.In the present study, we have found that elevation of the glucose concentration in the medium perfusing the isolated rat liver promotes net synthesis of glycogen by conversion of glycogen synthetase to the active form9 and transformation of glycogen phosphorylase to the inactive form. These effects of glucose appear to be independent of changes in the tissue level of cyclic AMP. 383

show abstract

supporting

confidence: 89%

Effects of Glucose on Glycogen Synthetase, Phosphorylase, and Glycogen Deposition in the Perfused Rat Liver

Buschiazzo

Exton

Park

1970

Proc. Natl. Acad. Sci. U.S.A.

102

View full text Add to dashboard Cite

show abstract

“…These have been resolved by electrophoresis (Katzen et al, 1965) into three 'low Kmn' hexokinases (EC 2.7.1.1) and one 'high-Km' glucokinase (EC 2.7.1.2). The presence of this high-Kmn, insulin-inducible, glucokinase has been correlated with the responsiveness of the liver to glucose at concentrations in the range normally observed for this sugar in the blood (Cahill et al, 1959;Di Pietro et al, 1962). This apparent duplication of glucose-phosphorylating capacities, considered together with the low total hexokinase activities (in the rat), has stimulated the suggestion that glucokinase alone is associated with the parenchymal cells and that the hexokinases occur in the mesenchymatous tissue (Kupffer cells etc.)…”

mentioning

confidence: 92%

Glycolytic and gluconeogenic enzyme activities in parenchymal and non-parenchymal cells from mouse liver

Crisp

Pogson

1972

Biochemical Journal

130

View full text Add to dashboard Cite

Parenchymal cells contain both glucose 6-phosphatase and fructose 1,6-diphosphatase. The non-parenchymal fraction appears to contain fructose 1,6-diphosphatase, but is devoid of glucose 6-phosphatase. 8. No aldolase A was detectable in the whole liver. Aldolase B occurs in both parenchymal and non-parenchymal tissue. 9. Parenchymal cells prepared by mechanical disruption ofmouse liver with 20 % polyvinyl alcohol exhibit a similar enzyme profile to those prepared enzymically. 10. The methodology involved in the preparation of isolated liver cells is discussed. The importance of the measurement of several parameters as criteria for establishing the viability of parenchymal cells is stressed. 11. The metabolic implications of the results in the present study are discussed.

show abstract

“…The role of the enzyme in the liver is to release glucose into the blood (2,7,22). The enzyme in the kidney may be related to the reabsorption of glucose (23), and the enzyme in jejunal epithelial cells may be concerned with absorption of nutrients (10).…”

Section: Discussionmentioning

confidence: 99%

Cytochemical glucose-6-phosphatase activity in human blood cells.

Kimura

1987

Acta Histochem. Cytochem

View full text Add to dashboard Cite

Blood glucose and the liver

Cited by 263 publications

References 134 publications

Effects of Glucose on Glycogen Synthetase, Phosphorylase, and Glycogen Deposition in the Perfused Rat Liver

Effects of Glucose on Glycogen Synthetase, Phosphorylase, and Glycogen Deposition in the Perfused Rat Liver

Glycolytic and gluconeogenic enzyme activities in parenchymal and non-parenchymal cells from mouse liver

Cytochemical glucose-6-phosphatase activity in human blood cells.

Contact Info

Product

Resources

About