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Fat Preference: A Novel Model of Eating Behavior in Rats
Published on: June 27, 2014
Ghrelin causes hyperphagia and obesity in rats
A M Wren1, C J Small, C R Abbott
1Endocrine Unit, Imperial College School of Medicine, Hammersmith Hospital, London, UK.
Diabetes
|October 27, 2001
Summary
Ghrelin, a stomach hormone, stimulates appetite and food intake. Fasting levels of ghrelin may increase food intake and contribute to long-term weight gain and adiposity.
Area of Science:
- Endocrinology
- Neuroscience
- Physiology
Background:
- Ghrelin is a peptide hormone produced in the stomach.
- It is known to stimulate food intake and growth hormone release.
Purpose of the Study:
- To determine the lowest effective dose of ghrelin for stimulating food intake.
- To compare plasma ghrelin concentrations during fasting and after ghrelin administration.
- To investigate the effects of ghrelin on food intake and body weight with chronic administration.
Main Methods:
- Determined the lowest orexigenic dose of ghrelin via intraperitoneal injection in rodents.
- Measured plasma ghrelin concentrations after injection and compared them to fasting levels.
- Microinjected ghrelin into specific hypothalamic nuclei, including the arcuate nucleus (Arc).
- Administered ghrelin systemically or intracerebroventricularly (ICV) for 7 days to assess chronic effects.
Main Results:
- The lowest effective dose of ghrelin for stimulating feeding was 1 nmol.
- Plasma ghrelin levels after 1 nmol injection were comparable to fasting levels.
- Ghrelin microinjected into the Arc significantly increased food intake (427% of control).
- Chronic systemic or ICV ghrelin administration led to increased cumulative food intake and significant weight gain and adiposity.
Conclusions:
- Ghrelin plays a crucial role in the long-term regulation of food intake and body weight.
- Circulating ghrelin at concentrations observed during fasting can stimulate appetite.
- The arcuate nucleus is a key hypothalamic site for ghrelin's orexigenic effects.
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