Remarkably, these genes were predominantly involved in lipid metabolism, carbon metabolism, and nitrogen metabolism in the mammary gland from the D vs. C (protein deficiency vs. protein adequacy) groups and two signaling pathways, Janus tyrosine kinase (JAK2)─Signal transducer and activator of transcription (STAT5) and peroxisome-proliferator-activated receptor (PPAR), from the DL vs. D (RPL supplementation vs. protein deficiency) groups (Figure 2B). Here, JAK2 is linked to hyperinsulinemic hypoglycemia, familial, 4.