Leptin synergizes with IL-1 in inducing nitric oxide synthase (NOS) type II. Synergistic effect of leptin (OB) on nitrite (NO2-) accumulation and NOS type II protein expression induced by IL-1. Stimulations were conducted in serum-free conditions (a,b) in ATDC5 chondrogenic cells and (c) in human primary chondrocytes. NO2- accumulation is selectively inhibited by aminoguanidine (AG) both in (d) ATDC5 cells and in (panel c) human primary chondrocytes. Values are expressed as mean ± standard error of the mean. WB, western blot.
Otero et al. Arthritis Research & Therapy 2005 7:R581 doi:10.1186/ar1708