ATP-binding cassette transporter A1 (ABCA1) as one kind of membrane protein was found recently to play a major role in cholesterol homeostasis. Angiotensin II (AngII) has been shown to possess several atherogenic properties. The aim of the study is to investigate the influence of AngII on the expression of ABCA1 and the content of cholesterol in THP-1 derived foam cells. Our study showed that: (1) reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting demonstrated that AngII down-regulated the expression of ABCA1 in a dose-dependent manner. (2) The content of cholesterol was negatively correlated with ABCA1. The results suggest the promoting effects of AngII on the forming of foam cells are in a dose-dependent manner via down-regulating the expression of ABCA1. (c) 2006 Elsevier Inc. All rights reserved.