ELECTRON-MICROSCOPIC AND RADIOIRON STUDIES OF IRON UPTAKE IN NEWBORN RAT MYOCARDIAL-CELLS INVITRO

Abstract

In vitro cultured myocardial cells from newborn rats are a good model system for the study of iron uptake and Fe metabolism. Ferric ammonium citrate was readily taken up by cells and about 50% of it was sequestered in ferritin. The rate of Fe uptake and/or accumulation in the cells was proportional to its concentration in the medium at 30, 60 and 90 .mu.M but was reduced at 180 .mu.M. At 360 .mu.M Fe the rate of uptake and the total Fe taken up was less than at 90 .mu.M Fe. EM examination showed endocytotic vesicles and lysosomes containing Fe-filled ferritin molecules and normal morphology. In control and experimental cultures there was an increase with time in the number of lysosomes. In the control cultures there were considerably fewer molecules of ferritin seen/lysosome than in experimentals. The number of ferritin molecules apparent in lysosomes increased with time and with increasing concentrations of Fe in the medium.