Regulation of Na+,K(+)-ATPase gene expression by insulin in vascular smooth muscle cells.
Na+,K(+)-ATPase gene expression and activity and its modulation by insulin were investigated in vascular smooth muscle cells (VSMC). Messenger RNAs encoding for alpha 1- and alpha 2-isoforms of Na+,K(+)-ATPase were identified in a pure population of cultured VSMC (a7r5 cells). The predominant isoform in VSMC was alpha 1, but only alpha 2 was regulated by insulin. Insulin treatment of VSMC for 1 and 6 h caused significant increases in mRNA encoding the alpha 2-subunit of Na+,K(+)-ATPase (n = 7, P < .01). Under similar conditions, insulin had no effect on alpha 1-Na+,K(+)-ATPase mRNA levels. VSMC treated with insulin exhibited a significant stimulation of ouabain inhibitable ATPase activity (1 h insulin, n = 3, v control, n = 3, P < .025; 6 h insulin, n = 3, v control, n = 3, P < .05). Changes in insulin regulation of Na+,K(+)-ATPase gene expression in vascular smooth muscle may be an important factor in the development of hypertension in diabetes.
Tirupattur
P R
PR
Department of Medicine, Wayne State University, Detroit, Michigan 48201.
Ram
J L
JL
Standley
P R
PR
Sowers
J R
JR
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D015971:Gene Expression Regulation, Enzymologic; D007328:Insulin / Q000502:physiology*; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000737:chemistry / Q000166:cytology / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics*; D014158:Transcription, Genetic
D007328:Insulin; D012333:RNA, Messenger; D000254:Sodium-Potassium-Exchanging ATPase