AJP - Regulatory, Integrative and Comparative Physiology, Vol 267, Issue 2 489-R495, Copyright © 1994 by American Physiological Society
Plasma-derived serum from hypertensive rats differentially increases growth of cultured arteriolar smooth muscle
H. W. Overbeck and R. K. Dubey
Department of Medicine, West Virginia University School of Medicine, Morgantown 26506.
A role for humoral factors in the arterial hypertrophy accompanying
hypertension has been suggested, but direct evidence is lacking. We
measured [3H]thymidine incorporation of growth-arrested smooth muscle
cells, cultured from renal preglomerular arterioles of normal rats and
exposed for 12 h to 10% platelet-poor plasma-derived serum (PDS) from male
rats with early, benign, one-kidney, one-clip hypertension and paired
one-kidney normotensive control rats. In the presence of low background
concentrations (1-2%) of fetal calf serum, PDS from hypertensive rats
increased [3H]thymidine incorporation up to 117% more than PDS from
normotensive rats (P < 0.0001). Results were similar for the < 10,000
mol wt fraction of PDS and for PDS from rats drinking saline vs. water or
eating a 7% (high) vs. a 0.45% NaCl diet. PDS from hypertensive rats also
differentially increased smooth muscle cell proliferation and c-fos mRNA
expression. Platelet-derived growth factor levels in PDS were undetectable
(< 0.17 ng/ml). This study provides evidence for altered concentrations
of sodium chloride-unresponsive plasma factor or factors in hypertension
that result in enhanced growth of arteriolar smooth muscle cells.
