Short-term hypothermia activates hepatic mitochondrial sn-glycerol-3-phosphate dehydrogenase and thermogenic systems.
The contribution of the sn-glycerol-3-phosphate (G-3-P) shuttle in the control of energy metabolism is well established. It is also known that its activity may be modulated by hormones involved in thermogenesis, such as thyroid hormones or dehydroepiandrosterone and its metabolites, that act by inducing de novo synthesis of mitochondrial G-3-P dehydrogenase (mGPDH). However, little is known as to the factors that may influence the activity without enzyme induction. In the present study we investigated the possible role of the G-3-P shuttle in the thermogenic response to different hypothermic stresses. It was found that a decrease of body temperature causes the liver rapidly to enhance mGPDH activity and G-3-P-dependent respiration. The enhancement, which does not result from de novo synthesis of enzymes, has the potential of increasing heat production both by decreased ATP synthesis during the oxidation of G-3-P and by activation of the glycolytic pathway.
Bobyleva
V
V
Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, Modena, Italy.
Pazienza
L
L
Muscatello
U
U
Kneer
N
N
Lardy
H
H
D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D004789:Enzyme Activation; D005260:Female; D005463:Fluoroacetates / Q000494:pharmacology; D005993:Glycerolphosphate Dehydrogenase / Q000378:metabolism*; D005994:Glycerophosphates / Q000378:metabolism; D006019:Glycolysis; D007035:Hypothermia / Q000201:enzymology* / Q000503:physiopathology*; D008297:Male; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D005463:Fluoroacetates; D005994:Glycerophosphates; D000255:Adenosine Triphosphate; D005993:Glycerolphosphate Dehydrogenase