Iron metabolism and haemoglobin formation in the embryonated hen egg. 1. The overall production of haem pigments during incubation

Abstract

A modification of the wet-digestion titanium-technic for total iron, suitable for appln. to eggs, is described. Total iron in 115 eggs has been found to avg. 1.07 mg. per egg. A modification of the 2:2-dipyridyl method for the detn. of non-heme iron is described. It is confirmed that almost the whole of the iron in unincubated hen eggs is non-heme iron. The increase in heme iron during the course of incubation is described. It amounted to 0.14 mg. per egg after 10 days'' incubation, 0.41 mg. at 14 days and 1 mg. at 21 days. During the last 9 days of incubation a fairly constant proportion of the total iron is present as heme iron at any given stage of development. This increases from 40% at 14 days to 72% at 21 days. Heme synthesis is discussed in relation to: (i) the total amt. of iron present, and (ii) the growth of the embryo and its membranes. Approx. hemoglobin values are calculated from the heme iron figures. It is concluded that the avg. egg on the point of hatching probably contains about 200 mg. of hemoglobin.