The response to the glucose challenge at t = 0.6 in both LF and HF is characterized by the up-regulation of Jun and Fos, together forming the transcription factor AP-1, and Il1a and Il1b. This might indicate that AP-1 initiates several processes in the early response to glucose, possibly activated by Il1, and that this mechanism is not influenced by obesity or insulin resistance. Here, IL1A is linked to obesity due to melanocortin 4 receptor deficiency.