Journal article
Increased Hypothalamic Signal Transducer and Activator of Transcription 3 Phosphorylation after Hindbrain Leptin Injection
Endocrinology (Philadelphia), Vol.151(4), pp.1509-1519
04/01/2010
Handle:
https://hdl.handle.net/2376/115805
PMCID: PMC2850241
PMID: 20185769
Abstract
Reduction of food intake and body weight by leptin is attributed largely to its action in the hypothalamus. However, the signaling splice variant of the leptin receptor, LRb, also is expressed in the hindbrain, and leptin injections into the fourth cerebral ventricle or dorsal vagal complex are associated with reductions of feeding and body weight comparable to those induced by forebrain leptin administration. Although these observations suggest direct hindbrain action of leptin on feeding and body weight, the possibility that hindbrain leptin administration also activates the Janus kinase/signal transducer and activator of transcription 3 (STAT3) signaling in the hypothalamus has not been investigated. Confirming earlier work, we found that leptin produced comparable reductions of feeding and body weight when injected into the lateral ventricle or the fourth ventricle. We also found that lateral and fourth ventricle leptin injections produced comparable increases of STAT3 phosphorylation in both the hindbrain and the hypothalamus. Moreover, injection of 50 ng of leptin directly into the nucleus of the solitary tract also increased STAT3 phosphorylation in the hypothalamic arcuate and ventromedial nuclei. Increased hypothalamic STAT3 phosphorylation was not due to elevation of blood leptin concentrations and the pattern of STAT3 phosphorylation did not overlap distribution of the retrograde tracer, fluorogold, injected via the same cannula. Our observations indicate that even small leptin doses administered to the hindbrain can trigger leptin-related signaling in the forebrain, and raise the possibility that STAT3 phosphorylation in the hypothalamus may contribute to behavioral and metabolic changes observed after hindbrain leptin injections.
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Details
- Title
- Increased Hypothalamic Signal Transducer and Activator of Transcription 3 Phosphorylation after Hindbrain Leptin Injection
- Creators
- Marieke Ruiter - Programs in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology, and physiology, Washington State University, Pullman, Washington 99164-6520Patricia Duffy - Programs in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology, and physiology, Washington State University, Pullman, Washington 99164-6520Steven Simasko - Programs in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology, and physiology, Washington State University, Pullman, Washington 99164-6520Robert C Ritter - Programs in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology, and physiology, Washington State University, Pullman, Washington 99164-6520
- Publication Details
- Endocrinology (Philadelphia), Vol.151(4), pp.1509-1519
- Academic Unit
- Integrative Physiology and Neuroscience, Department of
- Identifiers
- 99900547636701842
- Language
- English
- Resource Type
- Journal article