ESTRADIOL 17-?? REPRESSES INSULIN-LIKE GROWTH FACTOR I RECEPTOR EXPRESSION IN SMOOTH MUSCLE CELLS FROM RABBIT CARDIAC RECIPIENTS1

Autor: Hong Lou, Marie L. Foegh, Peter W. Ramwell
Rok vydání: 1998
Předmět:
Zdroj: Transplantation. 66:419-426
ISSN: 0041-1337
Popis: BACKGROUND A crucial step in cell cycle progression is the activation of the insulin-like growth factor I (IGF-I) receptor (IGF-IR) by its ligand. Earlier, we found estradiol 17-beta treatment of cardiac allograft recipients attenuates transplant arteriosclerosis; this was associated with inhibition of vascular cell proliferation induced by IGF-I. The current study demonstrates regulation of IGF-IR by estradiol 17-beta in vivo and in vitro in recipient native and allograft aorta and in aorta smooth muscle cells (SMCs). METHODS Twenty cardiac transplant recipient rabbits were treated with estradiol 17-beta (100 microg/kg/day) or placebo for 6 weeks. IGF-IR expression in the coronary arteries of rabbits was demonstrated by immunohistochemistry. Reverse transcription-polymerase chain reaction and RNase protection assay were used to detect IGF-IR mRNA in rabbit aortas and cultured aortic SMCs in the presence or absence of estradiol 17-beta in vitro. IGF-I-induced cell proliferation was performed with the aorta explants and aorta SMCs from estradiol- or placebo-treated rabbits. RESULTS Estradiol 17-beta treatment of rabbits significantly inhibited IGF-IR expression in the allograft coronary arteries and abrogated cell proliferation induced by IGF-I in the allograft aorta compared with placebo-treated recipients (65.4+/-5% vs. 500+/-139%, P
Databáze: OpenAIRE