Chronic protein restriction does not alter energetic efficiency or brown adipose tissue thermogenic capacity in genetically obese (fa/fa) Zucker rats

S. E. Specter, J. S. Hamilton, J. S. Stern, Barbara A Horwitz

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Attenuated regulatory thermogenesis in genetically obese (fa/fa) Zucker rats involves an impaired capacity to increase sympathetic drive to brown adipose tissue in response to dietary stimuli. Young, growing lean rats fed a low protein diet reduce energetic efficiency to compensate for elevated energy intake; however, it is not known if obese rats adapt similarly to chronic protein restriction by decreasing energetic efficiency and whether this would be accompanied by increased brown adipose tissue thermogenic capacity. Lean (Fa/Fa) and obese Zucker rats were either protein-restricted (protein 8% of total energy) or fed a control diet (21% protein) starting at age 5 wk. At 9 wk, oxygen consumption (VO2) was measured in response to an intubated meal of mixed macronutrient composition. Mass adjusted food intake (i.e., food intake/body weight0.67) was greater in protein-restricted than in control lean rats, but not different due to diet in obese rats. Mass- adjusted brown adipose tissue uncoupling protein levels were more than 100% greater in protein-restricted vs. control lean rats, but not different between protein-restricted and control obese rats. The uncoupling protein level was not significantly different in control lean vs. obese rats. Energetic efficiency was 40% lower in protein-restricted vs. control lean, but not different in obese rats; however, the efficiency of protein utilization was significantly greater in obese protein-restricted than in obese control rats. Meal-induced energy expenditure (VO2) did not differ significantly due to diet or genotype. In conclusion, protein restriction led to overfeeding in lean rats which appeared to enhance brown adipose tissue thermogenic capacity and decrease energetic efficiency. Protein efficiency increased to more than two times its original value in obese (fa/fa) rats, but otherwise no metabolic accommodation in the capacity for regulatory thermogenesis was observed in this genotype.

Original languageEnglish (US)
Pages (from-to)2183-2193
Number of pages11
JournalJournal of Nutrition
Volume125
Issue number8
StatePublished - 1995

Fingerprint

Zucker Rats
Brown Adipose Tissue
brown adipose tissue
energy efficiency
rats
Proteins
proteins
Thermogenesis
Diet
Meals
heat production
Eating
Genotype
food intake
Protein-Restricted Diet
diet
overfeeding
Leptin
Energy Intake
genotype

Keywords

  • brown adipose tissue
  • obesity
  • protein restriction
  • thermogenesis
  • Zucker rats

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Food Science

Cite this

Chronic protein restriction does not alter energetic efficiency or brown adipose tissue thermogenic capacity in genetically obese (fa/fa) Zucker rats. / Specter, S. E.; Hamilton, J. S.; Stern, J. S.; Horwitz, Barbara A.

In: Journal of Nutrition, Vol. 125, No. 8, 1995, p. 2183-2193.

Research output: Contribution to journalArticle

Specter, S. E. ; Hamilton, J. S. ; Stern, J. S. ; Horwitz, Barbara A. / Chronic protein restriction does not alter energetic efficiency or brown adipose tissue thermogenic capacity in genetically obese (fa/fa) Zucker rats. In: Journal of Nutrition. 1995 ; Vol. 125, No. 8. pp. 2183-2193.
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