Contribution of regional brain melanocortin receptor subtypes to elevated activity energy expenditure in lean, active rats

Highlights • We investigated the role of brain melanocortin receptors (MCRs) in the lean phenotype which shows high physical activity. • Lean rats showed elevated MCR expression specific to receptor subtype and brain region. • Lean rats’ physical activity was more responsive to MCR agonists and antagonist treatment. • There was correspondence between MCR expression pattern and regional response to brain MCR agonist and antagonist. • Hypothalamic MCR expression is integral to the high-activity phenotype.