CENTRAL INFUSIONS OF LEPTIN AND GLP-1-(7-36) AMIDE DIFFERENTIALLY STIMULATE C-FLI IN THE RAT-BRAIN

Recently, glucagon-like peptide-1-(7-36) amide (GLP-1) and leptin have been implicated in the regulation of food intake. In the present stud y, we compared the effects of third ventricular administration (i3vt) of leptin (3.5 mu g) and GLP-1 (10.0 mu g) on short-term food intake a nd c-Fos-like immunoreactivity (c-FLI) in hypothalamic, limbic, and hi ndbrain areas in the rat. Relative to controls, infusion of leptin or GLP-1 (3 h before lights off) significantly reduced food intake over t he first 2 h in the dark phase (53 and 63%, respectively). In differen t rats, infusion of leptin or GLP-1 elevated c-FLI in the paraventricu lar hypothalamus and central amygdala. Furthermore, leptin selectively elevated c-FLI in the dorsomedial hypothalamus, whereas GLP-1 selecti vely elevated c-FLI in the nucleus of the solitary tract, area postrem a, lateral parabrachial nucleus, and arcuate hypothalamic nucleus. The fact that most of the c-FLI after leptin or GLP-1 administration was observed in separate regions within the central nervous system (CNS) s uggests different roles for leptin and GLP-1 in the CNS regulation of food intake and body weight.