Characterisation of Ca2+ transport activity by white adipose tissue mitochondria.
Ca2+ transport in mitochondria isolated from rat white adipocytes has been examined and many of the properties found to be similar to those reported for mitochondria isolated from rat liver. Ca2+ transport is ruthenium red-sensitive (Ki approximately 5 pmol . mg protein-1), the affinity for free Ca2+ is high (Km approximately 3.3 microM) and the Vmax is 135 nmol Ca2+ . min-1 . mg protein-1 at 4 degrees C with 0.2 mM Pi present. Ca2+ transport is stimulated by increasing the medium [Pi], and is inhibited when ATP or Mg2+ is added to the incubation system and in contrast to brown adipocyte mitochondria, Ca2+ efflux is not promoted by Na+. White adipocyte mitochondria may play a rôle in the regulation of total cell calcium in this tissue.
D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000378:metabolism; D010710:Phosphates / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012430:Ruthenium Red / Q000494:pharmacology; D013347:Subcellular Fractions / Q000378:metabolism
D010710:Phosphates; D012430:Ruthenium Red; D002118:Calcium