|
|
||||||||
Obesity Research Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808
Removal of adrenal steroids by adrenalectomy (ADX) slows or reverses the development of many forms of obesity in rodents, including those that are leptin or leptin receptor deficient. Obesity is associated with hyperleptinemia and leptin resistance. We hypothesized that glucocorticoids impair leptin receptor signaling and that removal thereof would activate the Janus kinase (JAK)-signal transducers and activators of transcription (STAT) signaling pathway. The inhibitory effect of leptin (2.5 µg icv) on food intake was enhanced in ADX rats. A combination of ribonuclease protection assays, RT-PCR, Western blots, and mobility shift assays was used to evaluate the leptin signaling pathway in whole hypothalami from sham-operated, ADX and corticosterone-replaced ADX (ADX-R) Sprague-Dawley rats that were treated acutely with either saline vehicle or leptin intracerebroventricularly. ADX increased the expression of leptin receptor mRNA, increased STAT-3 mRNA and protein levels, induced constitutive STAT-3 phosphorylation and DNA binding activity, and also reduced suppressor of cytokine signaling-3 (SOCS-3) mRNA and protein levels. ADX and leptin treatment increased STAT-3 phosphorylation, but with no concomitant increase in DNA binding activity. Leptin and ADX decreased NPY mRNA expression, but their combination did not further decrease NPY mRNA. Corticosterone supplementation of ADX rats partially reversed many of these effects. In conclusion, ADX through activation of STAT-3 and inhibition of SOCS-3 activates the JAK-STAT signaling pathway. These effects most probably explain the ability to prevent the development of obesity by removal of adrenal steroids.
leptin; leptin receptor; glucocorticoids; signal transducers and activators of transcription-3; suppressor of cytokine signaling-3
This article has been cited by other articles:
![]() |
Y. Nishida, M. Yoshioka, and J. St-Amand Regulation of hypothalamic gene expression by glucocorticoid: implications for energy homeostasis Physiol Genomics, March 13, 2006; 25(1): 96 - 104. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. P. Coll, B. G. Challis, M. Lopez, S. Piper, G. S.H. Yeo, and S. O'Rahilly Proopiomelanocortin-Deficient Mice Are Hypersensitive to the Adverse Metabolic Effects of Glucocorticoids Diabetes, August 1, 2005; 54(8): 2269 - 2276. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. E. Wisse, K. Ogimoto, G. J. Morton, C. W. Wilkinson, R. S. Frayo, D. E. Cummings, and M. W. Schwartz Physiological regulation of hypothalamic IL-1{beta} gene expression by leptin and glucocorticoids: implications for energy homeostasis Am J Physiol Endocrinol Metab, December 1, 2004; 287(6): E1107 - E1113. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. CANNON and J. NEDERGAARD Brown Adipose Tissue: Function and Physiological Significance Physiol Rev, January 1, 2004; 84(1): 277 - 359. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. L. Drazen, M. D. Wortman, M. W. Schwartz, D. J. Clegg, G. van Dijk, S. C. Woods, and R. J. Seeley Adrenalectomy Alters the Sensitivity of the Central Nervous System Melanocortin System Diabetes, December 1, 2003; 52(12): 2928 - 2934. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Michel, B. E. Levin, and A. A. Dunn-Meynell Stress facilitates body weight gain in genetically predisposed rats on medium-fat diet Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2003; 285(4): R791 - R799. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. A. Cupples Peptides that regulate food intake Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2003; 284(6): R1370 - R1374. [Full Text] [PDF] |
||||
![]() |
A. M. Madiehe, T. D. Mitchell, and R. B. S. Harris Hyperleptinemia and reduced TNF-alpha secretion cause resistance of db/db mice to endotoxin Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2003; 284(3): R763 - R770. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |