Plasma Iron Transport During Egg Laying and After Oestrogen Administration in the Domestic Fowl (Gallus Domesticus)

Abstract

The concentrations of 69Fe and of radioiodinated transferrin and albumin were measured in the blood, liver, spleen, bone marrow and ova at different times after the injection of transferrin-bound 59Fe and the labelled proteins into non-laying, laying and oestrogen treated chickens. In the egg-laying and oestrogen-treated birds the 59Fe of the plasma was rapidly transferred from transferrin to another component with the properties of the phosphoprotein, phosvitin. Radioactive iron, and labelled transferrin and albumin to a lesser extent, entered the ova only while they were in the ovary. Relatively more labelled transferrin than albumin was found in all the tissues studied except in the ova, in which the two labelled proteins were present in the same relative concentration as in the plasma. It is concluded that, during egg laying and after oestrogen treatment, plasma iron bound to transferrin is taken up by the liver, incorporated into phosvitin and is then secreted into the plasma leading to elevation of the plasma iron concentration and transfer of iron to the ova.

Iron Metabolism in Pigeons

“…On the contrary the results of Morgan [1975] on laying hens, show a very fast uptake of iron for the liver, on the 15th day containing 10% of the radioiron.…”

“…The TIBC was 950 yugFe. 100-1ml, lower than the PI as has been shown in other birds [Planas, Castro and Recio, 1961], where plasma iron transport is carried out by transferrin and by phosvitin [Ali and Ramsay, 1968;Morgan, 1975].…”

“…In the same species Morgan [1975] analyzed the 59Fe concentration, after 6 h had elapsed in blood, liver spleen, bone marrow and ova in a study of the role of phosvitin in iron transport. Other work in birds refer only to the blood uptake in chickens [Halkett, Peters and Ross, 1958;Ramsay, 1966;Rusov, 1965;Godet and Belhani, 1974;Visco and Hogan, 1974] or in ducks [Klein, 1959;Jensen et al, 1953].…”

“…Ramsay and Campbell [1954] first observed increased plasma iron values during the laying period in chickens and Halkett, Peters and Ross [1958] analyzed the transference of 59Fe from plasma to the eggs in the same species. Godet and Belhani [1974] analyzed blood and organ distribution of 59Fe and Morgan [1975] the plasma iron transport in laying hens and the distribution in some organs; Klein [1959] made similar observations in ducks.The uptake of Fe in red cells in vivo has been analyzed in chickens [Ramsay, 1966], in ducks [Jensen, Ashenbrucker, Cartwright and Wintrobe, 1953] and in pigeons [Hammel and Bessman, 1964] where the Hb synthesis in the adult avian erythrocyte was noted. In pigeons, we recently observed [Palomeque and Planas, 1978] very high values in blood volume, haematocrit, haemoglobin concentration and in heart and breast muscle weights, suggesting an adaptation to flying habits.…”

Entry of iron into cells: A new role for the transferrin receptor in modulating iron release from transferrin

“…The affinity of phosphate for iron has long been known and is exploited by the egg yolk protein phosvitin for binding and transport of iron in the chick embryo [58]. Untargeted release of even trace amounts of iron from transferrin to phosphate groups of the cell membrane might be sufficient to promote lipid peroxidation in the membrane [57}.…”