Regulation of glucose transporter messenger RNA in insulin-deficient states.
Recent studies have indicated that a family of structurally related proteins with distinct but overlapping tissue distributions are responsible for facilitative glucose transport in mammalian tissues. Insulin primarily stimulates glucose transport by inducing the redistribution of a unique glucose transporter protein from an intracellular pool to the plasma membrane. This 509-amino-acid integral membrane protein, termed GLUT-4, is the main insulin-responsive glucose transporter in adipose and muscle tissues. We have observed a dramatic decrease (tenfold) in the steady-state levels of GLUT-4 messenger RNA in adipose tissue from fasted rats or rats made insulin deficient with streptozotocin. Insulin treatment of the streptozotocin-diabetic rats or refeeding the fasted animals causes a rapid recovery of the GLUT-4 mRNA to levels significantly above those observed in untreated control animals. By contrast, the levels of the erythrocyte/HepG2/rat brain-type glucose transporter mRNA remain essentially unchanged under these conditions. These data suggest that the in vivo expression of GLUT-4 mRNA in rat adipose tissue is regulated by insulin.
Sivitz
W I
WI
Department of Physiology & Biophysics, University of Iowa, Iowa City 52242.
DeSautel
S L
SL
Kayano
T
T
Bell
G I
GI
Pessin
J E
JE
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005215:Fasting; D005786:Gene Expression Regulation; D007328:Insulin / Q000502:physiology*; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D001786:Blood Glucose; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger