Circulating Ghrelin Levels and Central Ghrelin Receptor Expression are Elevated in Response to Food Deprivation in a Seasonal Mammal (Phodopus sungorus)
| Autor: | Michael Helwig, R. M. H. Khorooshi, Zoe A. Archer, Alexander Tups, Julian G. Mercer, Martin Klingenspor |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
medicine.medical_specialty
Phodopus Peptide Hormones Photoperiod Endocrinology Diabetes and Metabolism Receptor expression media_common.quotation_subject Growth hormone secretagogue receptor Hamster Receptors G-Protein-Coupled Cellular and Molecular Neuroscience Endocrinology Cricetinae Internal medicine medicine Animals RNA Messenger Receptors Ghrelin Receptor media_common biology Endocrine and Autonomic Systems Leptin Body Weight digestive oral and skin physiology Arcuate Nucleus of Hypothalamus Appetite Feeding Behavior biology.organism_classification Adaptation Physiological Ghrelin Up-Regulation Ventromedial Hypothalamic Nucleus Body Composition Seasons Food Deprivation |
| Zdroj: | Journal of Neuroendocrinology. 16:922-928 |
| ISSN: | 1365-2826 0953-8194 |
| Popis: | Ghrelin is an endogenous ligand for the growth hormone secretagogue receptor (GHSR). However, the functional interaction of ligand and receptor is not very well understood. We demonstrate that GHSR mRNA is up-regulated after food deprivation (48 h) in the hypothalamic arcuate nucleus and ventromedial nucleus of the seasonal Siberian hamster, Phodopus sungorus. This increase is accompanied by a two-fold elevation of circulating ghrelin concentration. Chronic changes in feeding state imposed by food restriction over a period of 12 weeks during long day-length induced increased GHSR gene expression, whereas food restriction for 6 weeks had no effect. Phodopus sungorus reveals remarkable seasonal changes in body weight, fat mass and circulating leptin levels. Ghrelin is generally regarded as having opposing effects on appetite and body weight with respect to those exhibited by leptin. However, our study revealed that seasonal adaptations were not accompanied by changes in either GHSR gene expression or circulating ghrelin concentration. Therefore, we suggest that ghrelin only plays a minor role in modulating long-term seasonal body weight cycles. Our findings imply that ghrelin predominantly acts as a short-term regulator of feeding. |
| Databáze: | OpenAIRE |
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