Evidence that the acute unmasking of GDP-binding sites in brown adipose tissue mitochondria is not dependent on mitochondrial swelling.
The role of mitochondrial swelling in the unmasking of GDP-binding sites on brown adipose tissue mitochondria has been examined in mice. Acute cold exposure (6 degrees C for 1 h) led to increases in GDP binding without changes in the concentration of uncoupling protein, indicating that an unmasking of binding sites had occurred. Measurements of mitochondrial matrix volume suggested that an acute unmasking of GDP-binding sites took place without swelling of the mitochondria. In addition, the induction of a rapid preswelling of the mitochondria by incubation in KCl in the presence of valinomycin did not affect the cold-induced unmasking of GDP-binding sites. It is concluded that the acute unmasking of GDP-binding sites on uncoupling protein in brown adipose tissue is not due simply to mitochondrial swelling.
Milner
R E
RE
Department of Medicine, University of Alberta, Edmonton, Canada.
Trayhurn
P
P
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D003080:Cold Temperature; D006150:Guanine Nucleotides / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000378:metabolism*; D006358:Hot Temperature; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008928:Mitochondria / Q000378:metabolism*; D008933:Mitochondrial Swelling; D011189:Potassium Chloride / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
D006150:Guanine Nucleotides; D006153:Guanosine Diphosphate; D014634:Valinomycin; D011189:Potassium Chloride