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Bioscience Reports

, Volume 4, Issue 6, pp 523–533 | Cite as

Acute influences on the two GDP-binding sites in brown-adipose-tissue mitochondria

  • K. R. Bryant
  • N. J. Rothwell
  • M. J. Stock
Article
  • 4 Downloads

Abstract

Scatchard analysis of3H-guanosine diphosphate (GDP) binding to rat brown-adipose-tissue mitochondria demonstrated that binding to the high- and low-affinity sites (Kd=0.05 and 2.0 μM) was abolished by denaturation at 100°C but non-specific binding remained constant (0.2% of free-GDP). Prior incubation of mitochondria at 37°C reduced binding to the high-affinity site, but this could be reversed by incubating samples at 0°C. Addition of palmitic acid (5–40 nmole/mg of mitochondrial protein) did not affect GDP-binding, but similar concentrations of palmitoyl CoA caused a slight reduction in the number of high-affinity sites and a significant decrease in the number of lower-affinity sites. Acute treatments known to stimulate thermogenesis in vivo (a single meal, cold exposure, or noradrenaline injection 40–80 min before sacrifice) all increased binding to both binding sites, and tended to raise the dissociation constants, whereas injection of 2-deoxy-D-glucose, which depresses metabolic rate in the rat, decreased dissociation constants of both sites and the maximum number of high-affinity sites. These data indicate that both GDP-binding sites respond rapidly to acute thermogenic stimuli, possibly due to conformational changes in the mitochondrial inner membrane, and that palmitoyl CoA may influence mitochondrial proton conductance via an association with purine nucleotide binding sites.

Keywords

Palmitic Acid Dissociation Constant Proton Conductance Cold Exposure Palmitoyl 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Giratdier L (1983) Brown fat: An energy dissipating tissue. in: Mammalian Thermogenesis (Girardier L & Stock MJ, eds), pp 50–98, Chapman and Hall, London.Google Scholar
  2. 2.
    Rothwell NJ & Stock MJ (1983) Acute effects of fat and carbohydrate on metabolic rate in normal, cold-acclimated and lean and obese (fa/fa) Zucker rats. Metabolism32, 371–376.PubMedGoogle Scholar
  3. 3.
    Rothwell NJ & Stock MJ (1983) Brown adipose tissue. In: Rec. Adv. Physiol. −10 (Baker PF, ed), pp. 349–384, Churchill Livingstone, Edinburgh.Google Scholar
  4. 4.
    Brooks SL, Rothwell NJ & Stock MJ (1982) Effects of diet and acute noradrenaline treatment on brown adipose tissue development and mitochondrial purine nucleotide binding. Q. J. Exp. Physiol.67, 259–268.PubMedGoogle Scholar
  5. 5.
    Desautels M & Himms-Hagen J (1979) Roles of noradrenaline and protein synthesis in the cold-induced increase in purine nucleotide binding by rat brown adipose tissue mitochondria. Can. J. Biochem.57, 968–976.PubMedGoogle Scholar
  6. 6.
    Winter PD (1983) Pharmacologycal control of thermogenesis and energy balance. PhD Thesis, Univ. London.Google Scholar
  7. 7.
    Nicholls DG & Locke R (1983) Cellular mechanisms of heat dissipation. In: Mammalian Thermogenesis (Girardier L & Stock MJ, eds), pp. 8–49, Chapman and Hall, London.Google Scholar
  8. 8.
    Sundin U & Cannon B (1980) GDP-binding to the brown fat mitochondria of developing and cold-adapted rats. Comp. Biochem. Physiol.65B, 463–471.Google Scholar
  9. 9.
    Desautels M & Himms-Hagen J (1981) Brown adipose tissue mitochondria of cold acclimated rats; change in characteristics of purine nucleotide control of the proton electrochemical gradient. Can. J. Biochem.59, 619–625.PubMedGoogle Scholar
  10. 10.
    Bryant KR, Rothwell NJ, & Stock MJ (1983) Identification of two mitochondrial GDP-binding sites in rat brown adipose tissue. Biosci. Rep.3, 589–598.PubMedGoogle Scholar
  11. 11.
    Rial E & Nicholls DG (1983) The regulation of the proton conductance of brown fat mitochondria: Identification of functional and non-functional sites. FEBS Lett.161, 284–288.PubMedGoogle Scholar
  12. 12.
    Lin C & Klingenberg M (1982) Characteristics of the isolated purine nucleotide binding protein from brown fat mitochondria. Biochemistry21, 2950–2956.PubMedGoogle Scholar
  13. 13.
    Locke RM, Rial E, Scott ID & Nicholls DG (1982) Fatty acids as acute regulators of the proton conductance of hamster brown fat mitochondria. Eur. J. Biochem.129, 373–380.PubMedGoogle Scholar
  14. 14.
    Cannon B, Sundin U & Romert L (1977) Palmitoyl coenzyme A: a possible physiological regulator of nucleotide binding to brown adipose tissue mitochondria. FEBS Lett.74, 43–46.PubMedGoogle Scholar
  15. 15.
    Lin C & Klingenberg M (1982) Characteristics of the isolated purine nucleotide binding protein from brown fat mitochondria. Biochemistry21, 2950–2956.PubMedGoogle Scholar
  16. 16.
    Rothwell NJ, Saville ME & Stock MJ (1982) Factors influencing the acute effect of food on oxygen consumption in the rat. Internat. J. Obesity.6, 53–59.Google Scholar
  17. 17.
    Rothwell NJ, Saville ME & Stock MJ (1981) Acute effects of food, 2-deoxy-D-glucose and noradrenaline on metabolic rate and brown adipose tissue in normal and atropinised lean and obese (fa/fa) Zucker rats. Pflügers Archiv.392, 172–177.Google Scholar

Copyright information

© The Biochemical Society 1984

Authors and Affiliations

  • K. R. Bryant
    • 1
  • N. J. Rothwell
    • 1
  • M. J. Stock
    • 1
  1. 1.Department of PhysiologySt. George's Hospital Medical SchoolLondonU.K.

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