Brown adipose tissue in genetically obese (fa/fa) rats: response to cold and diet

Young genetically obese (fatty, fa/fa) rats (7-8 wk old) maintained on a chow diet at 28 degrees C have a relatively normal amount of brown adipose tissue (BAT) (normal protein content, normal noradrenaline content, normal or slightly reduced cytochrome oxidase content, 30% reduction in DNA content)...

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Bibliographic Details
Published inThe American journal of physiology Vol. 244; no. 2; pp. E145 - E150
Main Authors Triandafillou, J, Himms-Hagen, J
Format Journal Article
LanguageEnglish
Published United States 01.02.1983
Subjects
Adipose Tissue - physiology
Adipose Tissue - physiopathology
Adipose Tissue, Brown - physiology
Adipose Tissue, Brown - physiopathology
Animals
Cold Temperature
Diet
diet-related diseases
DNA - analysis
Electron Transport Complex IV - metabolism
Female
Guanosine Diphosphate - metabolism
human nutrition
Male
Mitochondria - metabolism
Norepinephrine - analysis
Obesity - physiopathology
Proteins - analysis
Rats
Rats, Zucker
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Summary:Young genetically obese (fatty, fa/fa) rats (7-8 wk old) maintained on a chow diet at 28 degrees C have a relatively normal amount of brown adipose tissue (BAT) (normal protein content, normal noradrenaline content, normal or slightly reduced cytochrome oxidase content, 30% reduction in DNA content) with cells grossly hypertrophied by accumulation of lipid. The binding of purine nucleotides by BAT mitochondria is lower in fa/fa rats than in lean rats, suggesting a lesser thermogenic activation of this tissue. Acute exposure to cold (24 h at 4 degrees C) activates BAT thermogenesis (visible hyperemia, marked increase in mitochondrial binding of purine nucleotides, depletion of noradrenaline content) in fa/fa rats as in lean rats. In contrast, feeding a cafeteria diet to young fa/fa rats fails to activate BAT (no increase in mitochondrial binding of purine nucleotides) as it does in lean rats, and these rats accumulate more extra fat (increase in weight of gonadal white adipose tissue) than do cafeteria diet-fed lean rats. It is concluded that the young fa/fa rat has normal cold-induced nonshivering thermogenesis in BAT but defective diet-induced thermogenesis in BAT and that the consequent reduction in energy expenditure, coupled with hyperphagia, contributes to the development of its obesity. The most probable location for the defect is suggested to be associated with the hypothalamus.
ISSN:0002-9513
2163-5773
DOI:10.1152/ajpendo.1983.244.2.E145