Fig. 4.

Production of endogenous melanocortin peptides in arthritic mouse joints and primary macrophages. a Wrists joints from K/BxN arthritic mice (wild type and Mc3r−/−) were collected at day 8 and protein extracts prepared on RIPA buffer. The melanocortin peptides αMSH, γMSH, and ACTH were determined by enzyme immunoassay following manufacturers’ protocol. b Biogel-elicited macrophages were collected from mice (wild type and Mc3r−/−) 4 days after an i.p. injection with 1 ml of 2% biogel. Cells were cultured in vitro during 24 h in 10% FCS-RPMI. Supernatants were analyzed for αMSH, γMSH, and ACTH levels by enzyme immunoassay. Data are mean ± SEM of n = 5; p < 0.05 ANOVA followed by Bonferroni multiple comparison test K/BxN vs. Ctrl (*) or WT vs. Mc3r−/− (^#)