Vol. 277, Issue 2, H499-H507, August 1999
Interaction of angiotensin II and the insulin-like growth
factor system in vascular smooth muscle cells
Thomas
Gustafsson1,
Peter
Andersson1,
Yun
Chen1,
Jan Olof
Magnusson2, and
Hans J.
Arnqvist2
Departments of 1 Biomedicine
and Surgery and 2 Medicine and
Care, Faculty of Health Sciences, Linköping University, S-581
85 Linköping, Sweden
We studied the effects and interactions of ANG
II and the insulin-like growth factor (IGF) system in cultured rat
aortic smooth muscle cells. ANG II (1 µM) and IGF-I (10 nM)
stimulated both DNA and protein synthesis. The effects of the two
peptides in combination were additive or more than additive. The
AT1 receptor antagonist losartan
(10 and 100 µM) blocked their synergistic effect on DNA synthesis.
IGF binding protein (IGFBP)-1 inhibited the effect of IGF-I but not
that of ANG II on DNA synthesis. IGF-I stimulated gene expression of
IGFBP-2 and IGFBP-4. ANG II decreased IGF-I, IGFBP-2, and IGFBP-4
transcripts but increased the IGF-I receptor transcript. IGF-I and ANG
II in combination had similar effects on gene expression as ANG II
alone. The IGFBP-2 and IGFBP-4 peptides could be detected in the
conditioned medium. Our results show that ANG II and IGF-I have
synergistic effects on vascular smooth muscle cells and that they
interact in several ways.
growth; gene expression; insulin-like growth factor binding
protein; losartan
