Leptin activates STAT3 phosphorylation in hypothalamic nuclei of C57BL/6J mice.

Shown are light microscopy (LM) images of phospho-STAT3 immunoreactivity (IR) (DAB) in coronal brain sections of the mediobasal hypothalamus from 8-12 weeks old wild type C57BL/6J male mice. Animals were given vehicle or leptin (5 mg/kg, ip) and sacrificed after 30 minutes. Weak pSTAT3 IR is detected in the arcuate nucleus of the vehicle treated animals. In contrast, robust pSTAT3 IR is found in the LHA, VMH, DMH, Arc and PMN of the leptin-treated mouse. Three matched rostral-to-caudal sections are shown for both treatment groups. Boxes 1-4 are magnified in Figure 2. LHA: lateral hypothalamic area; VMH: ventro-medial hypothalamic nucleus; DMH: dorso-medial hypothalamic nucleus; Arc: arcuate hypothalamic nucleus; PMN: premammillary hypothalamic nucleus; fx: fornix, PH: posterior hypothalamic region; 3v: 3^rd ventricle.