Triiodothyronine increases glucose transporter isotype 4 mRNA expression, glucose transport, and glycogen synthesis in adult rat cardiomyocytes in long-term culture.
Effects of T3 treatment (day 2-day 12) on the expression of the insulin-regulated GLUT4, on 2-deoxyglucose uptake, and on glycogen synthesis were studied in ARC after 12 days of culture in T3-depleted 20% fetal calf serum. GLUT4 mRNA expression was low in controls, but increased in a dose-dependent manner by T3 treatment up to 2.8-fold at 100 nM. In parallel, 100 nM T3 increased basal 2-deoxyglucose uptake 1.95-fold and insulin-stimulated uptake 1.75-fold. In addition, T3 enhanced basal and insulin-stimulated [14C] glucose incorporation into glycogen 1.86- and 1.5-fold, respectively. Hence, ARC may meet part of their increased energy requirements in response to T3 by enhancing GLUT4 expression.
Gosteli-Peter
M A
MA
Department of Medicine, University Hospital, Zürich, Switzerland.
Schmid
C
C
Zapf
J
J
D000818:Animals; D001483:Base Sequence; D001692:Biological Transport; D002478:Cells, Cultured; D017931:DNA Primers; D003847:Deoxyglucose / Q000378:metabolism*; D005260:Female; D051275:Glucose Transporter Type 4; D006003:Glycogen / Q000096:biosynthesis* / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D007328:Insulin / Q000494:pharmacology; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000235:genetics* / Q000378:metabolism; D009124:Muscle Proteins; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014284:Triiodothyronine / Q000494:pharmacology*
D017931:DNA Primers; D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; C495694:Slc2a4 protein, rat; D014284:Triiodothyronine; D006003:Glycogen; D003847:Deoxyglucose