FERRITIN SYNTHESIS IN HUMAN EMBRYONIC AND FETAL TISSUES

Abstract

Ferritin synthesis by various tissues of the human conceptus was examined in the present study using tissue cultures. Normal embryonic and fetal tissues were obtained from 21 spontaneously or therapeutically aborted conceptuses of 29 days to 21 weeks of gestation. The tissues were cultured in the presence of 14C-amino acids and the culture fluids were examined for synthesized radioactive ferritin by means of immunodiffusion and autoradiography. Ferritin synthesis was detected in the earliest embryo studied, 29 days of gestation; this embryo was too small to permit culture of individual tissues and all tissues were cultured together. Ferritin synthesis by the liver and yolk sac was clearly established at the earliest stages in which these organs were cultured separately, 4.5 and 5.5 weeks of gestation, respectively. Synthesis of ferritin by bone marrow was detectable in some embryos at 8.5 weeks and was established in this tissue and in the spleen by 11 weeks. The chronological development of ferritin synthesis from liver and yolk sac to bone marrow and then spleen approximates the ontogenetic development of hematopoiesis. Ferritin synthesis was noted in the stomach and duodenum at 8.5 weeks, but was not well established at these sites until 21 weeks, suggesting possible induction of ferritin synthesis in the latter organs through fetal swallowing of amniotic fluid containing transferrin iron.