Insulin resistance has also been found to alter tau dephosphorylation via inhibition of adenosine monophosphate-activated kinase [208], and tau hyperphosphorylation has been observed in the hippocampi of the fa/fa rat model of obesity, with the extent of phosphorylation being increased in aged rats [209]. Here, MAPT is linked to obesity due to melanocortin 4 receptor deficiency.