Leptin Prevents Posthibernation Weight Gain But Does Not Reduce Energy Expenditure in Arctic Ground Squirrels
| Autor: | Mary Ann Pelleymounter, Margery Nicolson, Olav A. Ormseth, Brian M. Barnes, Bert B. Boyer, Loren Buck |
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| Rok vydání: | 1997 |
| Předmět: |
Leptin
Male medicine.medical_specialty Spermophilus Immunology Motor Activity Weight Gain Body Temperature Eating Weight loss Hibernation Internal medicine medicine Animals Telemetry Uncoupling protein Pharmacology biology digestive oral and skin physiology Proteins Sciuridae biology.organism_classification medicine.disease Obesity Recombinant Proteins Endocrinology Adipose Tissue Energy expenditure Basal metabolic rate Female medicine.symptom Energy Metabolism Weight gain |
| Zdroj: | Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology. 118:405-412 |
| ISSN: | 0742-8413 |
| Popis: | In mammals, leptin reduces energy intake and may increase energy expenditure as a means to maintain body weight and/or adiposity at an appropriate level. Hibernating mammals seasonally alter body mass, food intake, and body composition and, therefore, represent an attractive model for investigating the physiological regulation of changing body mass and adiposity. Previous experiments in our laboratory demonstrated that administration of mouse recombinant leptin reduces food intake and body weight in arctic ground squirrels during prehibernation fattening. In addition, leptin appeared to reduce metabolic efficiency (weight gain per unit of energy intake). This result suggests that reduced food intake alone may not account for the observed weight loss. Here, we describe the effect of a 3-week constant infusion of leptin given to posthibernation arctic ground squirrels on food consumption and energy expenditure. Mouse recombinant leptin (1 mg/ml) was administered through subcutaneously implanted mini-osmotic pumps (10 microliters/hr flow rate). Resting metabolic rate was monitored before and during the 3-week leptin administration period by indirect calorimetry. Body temperature and locomotory activity were monitored continuously by abdominal radiotransmitters. At the end of the leptin administration period, thermogenic capacity was evaluated by measuring brown fat uncoupling protein-1 mRNA and protein levels. Leptin administration resulted in reduced food intake and prevented posthibernation weight gain, but it did not alter any of the measured parameters of energy expenditure. |
| Databáze: | OpenAIRE |
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