Figure 3

Induction of SOCS1 and SOCS3 mRNA by leptin and IL-1β. A, RINm5F cells stably expressing wild type LEPRb were treated with leptin (100 ng/ml), IL-1β (50 U/ml) or a combination of both for the times indicated (1, 3, 7 or 16 h). B, RINm5F cells stably expressing the indicated LEPRb tyrosine mutants were treated with 100 ng/ml leptin (L) or vehicle (Ø) for 1 h. Total RNA was isolated and subjected to Northern blot analysis with cDNA probes for SOCS1, SOCS3 or ribosomal protein L4 (RPL4) as an unregulated control mRNA.