Capacity of transport of iron in the serum of birds and mammals in vitro" tests"

Abstract

A study has been made in vitro of the ca­pacity of transport of iron in serum of chic­kens and hens, and of two species of mam­mals (sheep and bull).

It has been demonstrated that the beha­viour of these serums in the face of growing additions of iron is clearly different. In the mammals, once the unsatured iron binding capacity of the transferrin has been passed values of nonfixed iron apear which are very close to those theoretically foreseen. In the birds, on the contrary, the serums can always fix a quantity of iron which is much higher than that corresponding to transferrin.

The experimental results obtained constitu­te a direct proof of the intervention in the serum of birds of a second protein mechanism for the transport of iron, which is in addition to the usual in all vertebrates, constituted by transferrin.

From other previously published papers, we consider to the conalbumin as this second iron transport system.