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Hypothalamic cocaine-amphetamine regulated transcript (CART) is regulated by glucocorticoids.
Niels Vrang1, Philip J Larsen, Mads Tang-Christensen
1Rheoscience, Glerupvej 2, 2610, Rodovre, Denmark. nv@ccbr.dk
Brain Research
|February 20, 2003
Summary
Glucocorticoids regulate Cocaine-amphetamine-regulated transcript (CART) gene expression in the rat hypothalamus. Dexamethasone treatment restored CART mRNA levels after adrenalectomy, indicating a glucocorticoid influence.
Area of Science:
- Neuroendocrinology
- Molecular Biology
- Gene Expression Regulation
Background:
- Cocaine-amphetamine-regulated transcript (CART) mRNA is abundant in the rat hypothalamus.
- CART peptides are involved in feeding behavior and HPA-axis regulation.
- Leptin regulates CART mRNA expression in the arcuate nucleus.
Purpose of the Study:
- To investigate the physiological regulation of CART gene expression.
- To examine the effects of adrenalectomy and glucocorticoid substitution on hypothalamic CART and POMC mRNA levels.
Main Methods:
- In situ hybridization was used to analyze mRNA levels.
- Adrenalectomy was performed on rats.
- Different glucocorticoid substitutions (corticosterone, dexamethasone) were administered.
Main Results:
- Adrenalectomy reduced CART mRNA levels in the paraventricular and arcuate nuclei.
- Dexamethasone treatment fully restored CART mRNA levels.
- Corticosterone pellet treatment did not restore CART mRNA levels.
- Hypothalamic POMC expression remained unaltered by adrenalectomy.
Conclusions:
- The CART gene is influenced by glucocorticoids.
- This regulation is likely mediated by a glucocorticoid receptor (GR) dependent mechanism.