Regulation of pdgf a: a possible mechanism for angiotensin ii
induced vascular growth.
Wang, Donna H., Russell L. Prewitt, Stephen J. Beebe.
Department of Internal Medicine, Hypertension and Vascular Research
Laboratories, University of Texas Medical Branch, Galveston, TX
77555, and Department of Physiology, Eastern Virginia Medical School,
Norfolk, VA 23501
APStracts 2:0053H, 1995.
This study was designed to determine the effects of angiotensin II
infusion on structure of conduit and resistance arteries and to see
if the effects correlate with changes in platelet-derived growth
factor (PDGF) A-chain gene and protein expression. Wistar rats were
subcutaneously infused by osmotic mini-pump with either angiotensin
II (AngII) at 200 ng/kg/min or physiological saline (control) for 14
days. Tailcuff systolic blood pressure was significantly higher in
the AngII compared to the control rats beginning the 2nd day of the
infusion and continuing to the end of the two weeks. Both aorta and
external spermatic artery (first-order arteriole of the cremaster
muscle) developed increased wall-to-lumen ratios in the AngII rats,
but this occurred by hypertrophy of the wall in the aorta and
reduction of the lumen in the arteriole. Digoxigenin-labeled cRNA
probes were used for in situ hybridization of vascular sections to
identify PDGF A mRNA. Gene expression of PDGF A in AngII rats was
upregulated in the hypertrophied aorta and in the non-hypertrophied
arteriole. With the use of immunocytochemistry techniques, PDGF A and
proliferating cell nuclear antigen (PCNA) were increased in the aorta
but not in the arterioles of the AngII rats compared to the control
rats. These results suggest that the difference in the growth
response between the aorta and the arteriole induced by AngII may lie
in posttranscriptional modification of PDGF A mRNA, differential
control of translation, or turnover of PDGF A protein.
Received 13 October 1994; accepted in final form 13 February
1995.
APS Manuscript Number H915-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 February 1995.