Energy balance and liver respiratory activity in rats fed on an energy-dense diet.
In the present study energy balance and liver respiratory activity were studied in rats fed on either a control diet or an energy-dense diet. Liver respiration was assessed both without added substrates and after the addition of hexanoate, glycerol, or sorbitol. The effect of ouabain on hexanoate-supported respiration was also determined. Metabolizable energy intake and energy expenditure increased in rats fed on an energy dense diet, but body-weight gain, as well as lipid and protein content, remained unchanged. When net energy expenditure, obtained excluding the total cost of storage, was expressed as a percentage of metabolizable energy, significant differences were found between the two groups of rats. This finding supports the presence of regulatory mechanisms in rats fed on an energy-dense diet, which are useful to counteract development of obesity. In addition, a significant increase in liver respiratory activity was found in rats fed on an energy-dense diet, both in the basal state and in that stimulated by added substrates. Na/K-pump-dependent O2 consumption also increased in rats fed on an energy-dense diet. The results indicate that a greater production of metabolic heat by the liver can contribute to the increased energy expenditure found in rats fed on an energy-dense diet.
Iossa
S
S
Department of General and Environmental Physiology, University of Naples "FEDERICO II", Italy.
Mollica
M P
MP
Lionetti
L
L
Barletta
A
A
Liverini
G
G
D000821:Animal Feed; D000818:Animals; D001833:Body Temperature Regulation; D002478:Cells, Cultured; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D010101:Oxygen Consumption; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000097:blood
D005230:Fatty Acids, Nonesterified; D014280:Triglycerides