Reciprocal changes in hypothalamic receptor binding and circulating leptin in anorectic tumor-bearing rats
Autor: | William T. Chance, Ambikaipakan Balasubramaniam, Fuping Peng, Jason Moore, Sulaiman Sheriff |
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Rok vydání: | 1998 |
Předmět: |
Leptin
Male medicine.medical_specialty Hypothalamus Receptors Cell Surface Anorexia Fatty Acids Nonesterified Biology Eating chemistry.chemical_compound Internal medicine medicine Animals Obesity Receptor Molecular Biology Leptin receptor Triglyceride General Neuroscience Body Weight digestive oral and skin physiology Proteins Fasting Neuropeptide Y receptor Rats Inbred F344 Rats Endocrinology chemistry Anorectic Receptors Leptin Sarcoma Experimental Neurology (clinical) medicine.symptom Carrier Proteins hormones hormone substitutes and hormone antagonists Protein Binding Developmental Biology |
Zdroj: | Brain Research. 803:27-33 |
ISSN: | 0006-8993 |
DOI: | 10.1016/s0006-8993(98)00545-9 |
Popis: | Although reduced biological activity of the obese gene product, leptin, has been associated with obesity, little information is available concerning leptin alterations during anorexia. Therefore, we measured circulating leptin concentrations and hypothalamic leptin binding in anorectic tumor-bearing and pair-fed control rats. Plasma concentrations of leptin decreased in tumor-bearing rats early in the course of tumor growth, and fell to nearly non-detectable levels during severe anorexia. The pair-fed control rats that ate the same amount of food as did the anorectic tumor-bearing rats exhibited a 50% decrease in plasma leptin concentration. Concentrations of free fatty acids were elevated in both tumor-bearing and pair-fed groups, while circulating levels of triglycerides were increased only in anorectic tumor-bearing rats. Leptin receptor density was doubled in the hypothalamus of tumor bearing rats, while binding affinity was decreased by 50%. These results suggest that peripheral leptin production is down-regulated, perhaps due to increased lipolysis in tumor-bearing rats. It appears that hypothalamic leptin systems up-regulate receptor numbers in response to decreased blood leptin level, however, the decrease in binding affinity may compensate for these alterations. Therefore, the influence of leptin on hypothalamic neuropeptide Y feeding systems may be minimal in anorectic tumor-bearing rats. |
Databáze: | OpenAIRE |
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