Regulation of glucose transporter glut4 and hexokinase ii gene
transcription by insulin and epinephrine.
Jones, Jared P., and G. Lynis Dohm.
Department of Biochemistry, East Carolina University School of
Medicine, Greenville, North Carolina 27858
APStracts 4:0144E, 1997.
Transport of glucose across the plasma membrane by GLUT4 and
subsequent phosphorylation of glucose by hexokinase II (HKII)
constitute the first two steps of glucose utilization in skeletal
muscle. This study was undertaken to determine whether epinephrine
and/or insulin regulate in vivo GLUT4 and HKII gene transcription in
rat skeletal muscle. In the first experiment, adrenodemedullated male
rats were fasted 24 h and sacrificed in the control condition or
after being infused 1.5 h with epinephrine (30 [mu]g/ml at 1.68
ml/h). In the second experiment, male rats were fasted 24 h and
sacrificed after being infused 2.5 h at 1.68 ml/h with saline or
glucose (625 mg/ml) or insulin (39.9 [mu]g/ml) + glucose (625 mg/ml).
Nuclei were isolated from pooled quadriceps, tibialis anterior, and
gastrocnemius muscles. Transcriptional run-on analysis indicated that
epinephrine infusion decreased GLUT4 and increased HKII transcription
compared to fasted controls. Both glucose and insulin + glucose
infusion induced increases in GLUT4 and HKII transcription of 2-fold
and 3 to 4-fold, respectively, compared to saline-infused rats. In
conclusion, epinephrine and insulin may regulate GLUT4 and HKII genes
at the level of transcription in rat skeletal muscle.
Received 26 March 1997; accepted in final form 19 June 1997.
APS Manuscript Number E138-7.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 10 July 1997