AJP - Heart and Circulatory Physiology, Vol 268, Issue 2 767-H772, Copyright © 1995 by American Physiological Society
Humoral factor(s) in hypertensive rats trophic for cultured aortic smooth muscle cells
H. W. Overbeck, G. Wu and J. P. Durham
Department of Medicine, West Virginia University School of Medicine, Morgantown 26506.
Humoral factors in one-kidney, one-clip (1K,1C) hypertension in rats
increase growth of smooth muscle cells cultured from rat arteries. To
further characterize the plasma factor or factors involved, we prepared
male rats with early, benign 1K,1C hypertension and paired them with
one-kidney (1K) normotensive controls. In the presence of growth stimulated
by background levels (1%) of fetal calf serum (FCS), plasma-derived serum
(PDS), fresh or frozen, from 99 1K,1C rats differentially increased
[3H]thymidine incorporation of growth-arrested rat aortic cells; increases
were up to 93% more than those evoked by the paired 1K PDS and were
concentration related (P < 0.01). However, there was no evidence for a
differential effect of 1K,1C PDS in the absence of FCS nor of PDS after
boiling. On the other hand, neither treatment of PDS with proteolytic
enzymes nor charcoal absorption ablated this differential trophic effect.
Thus this study provides evidence that the humoral factor(s) in
hypertension are resistant to freezing, proteolysis, and charcoal
absorption, but sensitive to boiling, and they require background levels of
growth for expression.
