AgRP neurons: a switch between peripheral carbohydrate and lipid utilization.

AgRP/NPY neurons are critical regulators of body weight and food intake. Concordant with their orexigenic effects, it is expected that AgRP ablation leads to the appearance of a lean phenotype. In the current issue of The EMBO Journal, Joly-Amado et al (2012) describe an obese phenotype in a model of AgRP-ablated mice, and link it to a shift in metabolic profile in efferent tissues such as the liver, muscle and pancreas. Hypothalamic AgRP/NPY neurons are known to play a key role in the regulation of body weight and food intake. With the advent of ‘toxin-receptor mediated cell knockout’ technology, several reports have tried to address the physiological relevance of this set of neurons. The ablation of Agrp-expressing neurons has different consequences depending on the age of the mice. Thus, in the neonatal stage, temporal deletion of AgRP neurons by diphtheria toxin