FGF21 and obesity due to melanocortin 4 receptor deficiency: In our chronic studies in diet-induced obesity model, we also observed significant menthol induced glucagon dependent changes, including an increase in serum glucagon/insulin ratio, decrease in liver glycogen content, decrease in liver weight, decrease in liver triglyceride levels, increase in serum glycerol content, increased expression of gluconeogenesis marker genes in liver, increase in FGF-21 and activation of AMPK.