Originally published in Acta Chem. Scand. 11, 120—124 (1957). 



63. HAEMOGLOBIN PRESENT 

 IN THE NUCLEAR FRACTION OF THE LIVER 



R. 



BoNNicHSEN, G. Ehrenstein, G. Hevesy and J. Schliack 



From the Institute for Organic Chemistry and Biochemistry, University of 



Stockholm, Sweden 



The nuclear fraction of 1 gm of rat and rabbit Hver contains 0.34 and 0.58 mgm 

 of in aqueous medium non-extractable haemoglobin. The corresponding figure 

 for the nuclei of the red corpuscles of 1 ml of hen's blood is 0.9 mgm. 



The haemoglobin content of the nuclear fraction of 1 gm of foetal rabbit liver 

 is 100 times as large as that of 1 gm of maternal liver. The ratio of their sspe content 

 11 to 17 h after labelling the maternal plasma iron, works out to be 100. 



One day or more after exposure of the rat to 500 r, incorporation of ^^Ye into 

 the non-extractable haemoglobin of the hver nucleus fraction is strongly depressed. 



As mentioned in a previous note (Bonnichsen et alM^) the nuclear 

 fraction of the liver of the guinea pig contains small amounts of haemo- 

 globin not extractable by saline or other aqueous solutions. This paper 

 contains data on the incorporation of ^aPe into this fraction isolated from 

 the liver of adult rats and rabbits and of that of the rabbit embryo. 

 This fraction was furthermore located in the nuclei of the erythrocytes 

 of the hen. 



That in the basophilic erythroblasts of human and rat bone marrow 

 the site of haemoglobin synthesis is primarily the nucleus, was repeatedly 

 suggested. The methods applied in these investigations were ultraviolet 

 absorption microspectroscopy and cytochemical staining procedures(2-9>. 



EXPERIMENTAL 



In 15 experiments with male rats an aggregate number of 173 animals, weigh- 

 ing between 150 and 280 gm were injected intraperitoneally with 0.25 ml of a 3.8% 

 ammonium-citrate solution containing 0.5—12 fxgm of with ^ ^Fe labelled iron of 

 0.1 — 12 [xC activity. Half the number of rats was exposed to 150 r — 500 r of X- 

 rays. Injection took place 15 min to 5 days after exposure. 



The animals were kiUed from 2 to 48 hr after injection. The livers were perfused 

 first with 0.145 M NaCl and then with 0.25 M sucrose containing 0.018 M CaClg. 

 The weighed livers were homogenized in 9 vols, of 0.25 M sucrose — 0.0018 M 

 CaClg. The further procedure was carried out according to Hogeboom et alS^^^ 



The nuclear fraction isolated by this procedure was cytologicaUy inhomogeneous. 

 The fraction contained about 60—80% of the cell nuclei, it also contained erythro- 

 cytes, connective tissue, residual intact cells and free mitochondria. 



