α-Melanocyte-stimulating hormone (α-MSH) is a hypothalamic neuropeptide proposed to play a key role in energy homeostasis. To investigate the behavioral, metabolic, and hypothalamic responses to chronic central α-MSH administration, α-MSH was infused continuously into the third cerebral ventricle of rats for 6 days. Chronic α-MSH infusion reduced cumulative food intake by 10.7% (P < 0.05 vs. saline) and body weight by 4.3% (P < 0.01 vs. saline), which in turn lowered plasma insulin levels by 29.3% (P < 0.05 vs. saline). However, α-MSH did not cause adipose-specific wasting nor did it alter hypothalamic neuropeptide mRNA levels. Central α-MSH infusion acutely activated neurons in forebrain areas such as the hypothalamic paraventricular nucleus, as measured by a 254% increase in c-Fos-like immunore-activity (P < 0.01 vs. saline), as well as satiety pathways in the hindbrain. Our findings suggest that, although an increase of central melanocortin receptor signaling acutely reduces food intake and body weight, its anorectic potency wanes during chronic infusion and causes only a modest decrease of body weight.
|Original language||English (US)|
|Journal||American Journal of Physiology - Regulatory Integrative and Comparative Physiology|
|Issue number||2 48-2|
|State||Published - 2000|
- Body weight
ASJC Scopus subject areas
- Physiology (medical)