TY - JOUR
T1 - Compartmentation of carbohydrate metabolism in vascular smooth muscle
T2 - evidence for at least two functionally independent pools of glucose 6-phosphate
AU - Lynch, Ronald M.
AU - Paul, Richard J.
N1 - Funding Information:
This work was supported in part by NIH 23240 and 22619. R.J.P. and an Established Investigator of the American Heart Association.
PY - 1986/8/1
Y1 - 1986/8/1
N2 - Previous work has indicated that there are at least two functionally independent Embden-Meyerhof pathways within the vascular smooth muscle of porcine carotid artery. We tested this hypothesis by analyzing the isotopic equilibrium between medium glucose and intracellular glucose 6-phosphate under basal conditions and after 30 min of mechanical activation, during which time the rate of glycogenolysis has been found to be substantial. Under basal conditions, the specific activity of glucose 6-phosphate equilibrated to a level which was not in isotopic equilibrium with medium glucose suggesting that there is a significant pool of glucose 6-phosphate which is not readily accessible to medium glucose. After 15 min of mechanical activation, the specific activity of intracellular glucose 6-phosphate was found to decrease significantly from its apparent steady-state distribution, indicating that glycogen was likely to be a significant source for glucose 6-phosphate. Since the specific activity of lactate was unaltered from its equilibrium distribution under similar stimulus conditions, these findings substantiate the existence of at least two independent pools of glucose 6-phosphate.
AB - Previous work has indicated that there are at least two functionally independent Embden-Meyerhof pathways within the vascular smooth muscle of porcine carotid artery. We tested this hypothesis by analyzing the isotopic equilibrium between medium glucose and intracellular glucose 6-phosphate under basal conditions and after 30 min of mechanical activation, during which time the rate of glycogenolysis has been found to be substantial. Under basal conditions, the specific activity of glucose 6-phosphate equilibrated to a level which was not in isotopic equilibrium with medium glucose suggesting that there is a significant pool of glucose 6-phosphate which is not readily accessible to medium glucose. After 15 min of mechanical activation, the specific activity of intracellular glucose 6-phosphate was found to decrease significantly from its apparent steady-state distribution, indicating that glycogen was likely to be a significant source for glucose 6-phosphate. Since the specific activity of lactate was unaltered from its equilibrium distribution under similar stimulus conditions, these findings substantiate the existence of at least two independent pools of glucose 6-phosphate.
KW - (Vascular smooth muscle)
KW - Carbohydrate metabolism
KW - Compartmentation
KW - Glucose 6-phosphate
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U2 - 10.1016/0167-4889(86)90159-X
DO - 10.1016/0167-4889(86)90159-X
M3 - Article
C2 - 3730432
AN - SCOPUS:0022502321
VL - 887
SP - 315
EP - 318
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
SN - 0167-4889
IS - 3
ER -