Messenger RNA Expression of Energy Regulating Neuropeptides in the Hypothalamus. Bars with the same identifying letters above them were significantly different from each other at the p < 0.05 level. A - C) AgRP, NPY and POMC mRNA levels, respectively, in the arcuate nucleus of the hypothalamus following the dietary manipulation period of 30 days. No significant differences were found across groups. D) CART mRNA expression in the arcuate nucleus of the hypothalamus following the 30 day dietary manipulation. There was a significant line by diet interaction for CART mRNA expression. Post-hoc analysis showed that CART mRNA in HCRs on the balanced diet was expressed at significantly lower levels than in HCRs on the unbalanced diet. Furthermore, CART mRNA expression in HCRs on the unbalanced diet was significantly higher than CART mRNA levels in LCRs on the unbalanced diet.