Angiotensin II (AngII) mediates hypoxia-induced leptin expression in HCASMCs. (A and B) AngII and leptin were measured in cell lysates and the culture medium by a quantitative, competitive Enzyme-linked immunosorbent assay (ELISA) using a specific anti-AngII and anti-leptin antibodies. *P < 0.01 vs. normoxia control. #P < 0.01 vs. 4 h (n = 3). (C and D) Hypoxia-induced leptin expression was suppressed by AngII antibody and losartan. Exogenous addition of AngII (under normoxia) also increased leptin expression. HCASMCs were subjected to normoxia or hypoxia for 4 h and total cell lysates were immunoblotted with anti-leptin antibody. Alpha-tubulin was used as a protein loading control in each lane. *P < 0.01 vs. normoxia control. #P < 0.01 vs. 4 h (n = 3).