Rapid changes in number of GDP binding sites on brown adipose tissue mitochondria
(TH)GDP binding to brown adipose tissue (BAT) mitochondria increased more than twofold in 20 min when rats were moved from 27 to 4C. When animals housed at 4C for 2 h were returned to 27C, GDP binding decreased sharply in 20 min and returned to control levels in 2 h. These results are consistent with a rapid unmasking and remasking of GDP bindings sites. GDP binding to mitochondria from warm and acutely cold treated rats was not modified by prior swelling, by freeze-thawing, nor by sonication of the mitochondria before assay. GDP-inhibitable proton conductance, as measured by passive swelling, was unaffected by this brief exposure to cold but more than doubled in rats kept at 4C for 10 days. The authors hypothesize that the rate of GDP-inhibitable swelling may be a reflection of uncoupling protein concentration in the BAT mitochondria, whereas physiological thermogenic activity is more appropriately indicated by GDP binding. The alterations in binding activity appear not to be due to changes in the mitochondrial membrane integrity.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 6281030
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 251:2
- Country of Publication:
- United States
- Language:
- English
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ADIPOSE TISSUE
PHYSIOLOGY
CARBON 14 COMPOUNDS
TRACER TECHNIQUES
MITOCHONDRIA
CONFIGURATION INTERACTION
NUCLEOTIDES
TRITIUM COMPOUNDS
GUANOSINE
RATS
RESPIRATION
TEMPERATURE DEPENDENCE
ANIMAL TISSUES
ANIMALS
AROMATICS
AZAARENES
BODY
CELL CONSTITUENTS
CONNECTIVE TISSUE
HETEROCYCLIC COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
NUCLEOSIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
PURINES
RIBOSIDES
RODENTS
TISSUES
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques