Ouabain- and marinobufagenin-induced proliferation of human umbilical vein smooth muscle cells and a rat vascular smooth muscle cell line, A7r5.
BACKGROUND
We studied the growth-promoting effects of 2 sodium pump-selective cardiotonic steroids, ouabain and marinobufagenin, on cultured cells from vascular smooth muscle (VSMCs) from human umbilical vein and a rat VSMC line, A7r5.


RESULTS
Both ouabain and marinobufagenin activated proliferation of these cells in a concentration-dependent manner, reflecting the cardiotonic steroid sensitivity of the specific alpha1 subunit contained within each cell source. The observed effective concentration ranges of both compounds was below that necessary to induce cytoplasmic ion alterations by sodium pump inhibition.


CONCLUSIONS
These data indicate that the ouabain-activated proliferative effect previously observed in canine VSMCs occurs in other VSMC sources. This growth effect seems to be initiated by drug interaction with the sodium pump, reflected by the affinity of the steroid for the pump, and is independent of altered transmembrane ionic gradients.
Abramowitz
Joel
J
Department of Medicine, Section of Cardiovascular Science, Baylor College of Medicine, Houston, Tex 77030, USA.
Dai
Cuiping
C
Hirschi
Karen K
KK
Dmitrieva
Renata I
RI
Doris
Peter A
PA
Liu
Lijun
L
Allen
Julius C
JC
D000818:Animals; D002018:Bufanolides / Q000494:pharmacology*; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D008024:Ligands; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D010042:Ouabain / Q000494:pharmacology*; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014471:Umbilical Veins / Q000166:cytology
D002018:Bufanolides; D002316:Cardiotonic Agents; D004791:Enzyme Inhibitors; D008024:Ligands; C093896:marinobufagenin; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase