Energy balance, thermogenesis and brown adipose tissue activity in tube-fed rats

J Nutr. 1984 Oct;114(10):1965-70. doi: 10.1093/jn/114.10.1965.

Abstract

Young adult male rats were given a portion (42%) of their normal daily food intake by stomach tube (tube-fed), but they were also allowed free access to the same powdered diet. Total metabolizable energy intake was identical to that of controls, but tube-fed rats gained 25% weight and 50% more body energy than controls over 15 days. Total energy expenditure and resting oxygen consumption, measured during the latter part of the day, were reduced in tube-fed rats. Intubated animals showed a lower thermogenic response to noradrenaline and depressed activity of the mitochondrial proton conductance pathway in brown adipose tissue (assessed from GDP-binding), but brown fat mass, protein content, the density of beta-adrenoreceptors in brown fat cell membranes and plasma triiodothyronine (T3) levels did not differ between groups. These data indicate that the enhanced energetic efficiency and fat deposition of tube-fed rats is due to a lower energy expenditure, resulting, at least in part, from lower levels of thermogenesis in brown adipose tissue.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue, Brown / metabolism*
  • Animals
  • Body Temperature Regulation* / drug effects
  • Body Weight
  • Energy Metabolism*
  • Intubation, Gastrointestinal
  • Male
  • Norepinephrine / pharmacology
  • Oxygen Consumption
  • Rats
  • Rats, Inbred Strains

Substances

  • Norepinephrine