Subcellular distribution of tissue radiocopper following intravenous administration of 67Cu-labeled Cu-PTSM.
The subcellular distribution of radiocopper in the brain and liver of rats has been determined following i.v. administration of Cu-PTSM, pyruvaldehyde bis(N4-methylthiosemicarbazonato)copper(II), labeled with copper-67. Homogenized tissue samples were separated by differential centrifugation into four subcellular fractions: (I) cell membrane + nuclei; (II) mitochondria; (III) microsomes; and (IV) cell cytosol. Upon sacrifice at 10 min post-Cu-PTSM injection, brain fractions, I, II, III and IV contain 35 +/- 12, 11 +/- 3, 2.8 +/- 1.3 and 51 +/- 7% of brain activity, respectively (n = 4). In animals sacrificed 24 h post-injection the subcellular fractions of brain tissue show little change from the radiocopper distribution seen at 10 min post-injection, although the mitochondrial fraction may contain slightly more tracer and the cytosolic fraction slightly less (I, 40 +/- 10%; II, 18 +/- 5%; III, 3.4 +/- 1.5%; and IV, 38 +/- 5%; n = 5). Subcellular fractions I, II, III and IV of liver contain 25 +/- 5, 12 +/- 3, 17 +/- 4 and 46 +/- 6% of 67Cu tracer in animals sacrificed 10 min post-Cu-PTSM injection. An identical subcellular distribution of 67Cu, was found in the liver following i.v. administration of ionic radiocopper (as Cu-citrate). The liver and brain cytosolic fractions at 10 min post-injection were further separated by Sephadex column chromatography. In liver cytosol, three different radiocopper components with molecular weights of about 140,000, 41,000-46,000 and 10,000-16,000 Da were found. In the brain supernatant fraction, most of the radiocopper was bound to a single low molecular weight cytosolic component (14,000-16,000 Da).(ABSTRACT TRUNCATED AT 250 WORDS)
Baerga
I D
ID
Department of Pharmacology and Toxicology, School of Pharmacy and Pharmacal Sciences, Purdue University, West Lafayette, IN 47907.
Maickel
R P
RP
Green
M A
MA
D000818:Animals; D001921:Brain / Q000378:metabolism; D002951:Citrates / Q000493:pharmacokinetics; D019343:Citric Acid; D003301:Copper Radioisotopes; D003600:Cytosol / Q000378:metabolism; D007275:Injections, Intravenous; D007424:Intracellular Fluid / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D051381:Rats; D011919:Rats, Inbred Strains; D013347:Subcellular Fractions / Q000378:metabolism; D013882:Thiosemicarbazones / Q000493:pharmacokinetics*; D014018:Tissue Distribution
D002951:Citrates; D003301:Copper Radioisotopes; D009942:Organometallic Compounds; D013882:Thiosemicarbazones; C052629:copper pyruvaldehyde bis(N(4)-methylthiosemicarbazone) complex; D019343:Citric Acid