Storage iron kinetics. I. Measurement of the cellular distribution of 59 Fe in rat liver
Cook, J.D.; Hershko, C.; Finch, C.A.
Journal of Laboratory and Clinical Medicine 80(5): 613-623
1972
ISSN/ISBN: 0022-2143 PMID: 5081660 Document Number: 52614
1. Female Wistar rats weighing from 170 to 200 g were given from 1 to 50 mg colloidal carbon particles by vein 10 min before death to label reticuloendothelial (RE) cells in the liver and for quantitative studies 1 mg polystyrene latex particles by vein 24 h before death. For radioactive labelling of RE cells chondroitin sulphate-59Fe was given by vein to provide from 10 to 100 mu g Fe 10 min before death. For radioactive labelling of parenchymal cells of liver 59Fe or 55Fe as FeCl3 was given by vein 30 min after the injection of 25 mg unlabelled iron sorbitex. When the rats were killed liver sections were prepared for autoradiography. Suspensions of liver RE cells were prepared by a modification of the method of Mills and Zucker-Franklin (American Journal of Pathology (1969) 54, 147) in which parenchymal cells are selectively destroyed by the proteolytic enzyme pronase. For each liver treated with pronase particle counts were made on 50 separated Kupffer cells. For each cell the number of latex particles and silver grains directly overlying the cell were recorded. By use of the ratio of grains to latex particles (GL ratio) errors introduced by differences in selection of cells for counting or incomplete recovery of Kupffer cells after pronase digestion were eliminated. That GL ratio as estimated in 100 cells was an exact measure of Kupffer cell radioactivity was shown when different rats were given the same amount of latex but increasing amounts of chondroitin sulphate-59Fe. There was a linear correlation between GL ratio and total liver radioactivity. The close agreement between parallel estimations of 59Fe distribution by quantitive autoradiography and the dual nuclide estimations showed that there was no interference by artifacts and that parenchymal 59Fe could be indirectly estimated by subtraction of RE cell radioactivity from total liver radioactivity.