Impact of hyperinsulinemia on myosin heavy chain gene regulation.
The purpose of this study was to determine whether hyperinsulinemia alters myosin heavy chain (MHC) gene expression in human skeletal muscle. A biopsy from the vastus lateralis was obtained in young, lean [age 24.6 +/- 1.0 (SE) yr, body fat 11.9 +/- 1.9%, body mass index 26.1 +/- 1.1 kg/m2; n = 10] men before and after 3 h of hyperinsulinemia (hyperinsulinemic-euglycemic clamp). Muscle was analyzed for mRNA of type I, IIa, and IIx MHC isoforms. Hyperinsulinemia (mean of 1,065.7 +/- 9.8 pmol/l during minutes 20 to 180) did not change (P > 0.05) the mRNA concentration of either the type I MHC or type IIA MHC isoforms. In contrast, type IIX MHC mRNA increased (P < 0.05) with hyperinsulinemia compared with the fasted condition. These data indicate that hyperinsulinemia rapidly increases type IIx MHC mRNA in human skeletal muscle.
Houmard
J A
JA
Human Performance Laboratory, Department of Exercise and Sport Science and School of Medicine, East Carolina University, Greenville, North Carolina 27858, USA. HOUMARDJ@MAIL.ECU.EDU
O'Neill
D S
DS
Zheng
D
D
Hickey
M S
MS
Dohm
G L
GL
D000328:Adult; D000818:Animals; D005786:Gene Expression Regulation / Q000502:physiology*; D015309:Glucose Clamp Technique; D006801:Humans; D006946:Hyperinsulinism / Q000378:metabolism*; D007536:Isomerism; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000096:biosynthesis* / Q000235:genetics*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats
D012333:RNA, Messenger; D018995:Myosin Heavy Chains