Haemoglobins of the foetal and adult rat: sites of synthesis and the effects of erythropoietin.

Early studies on rat haemoglobins indicated the existence of several components (Gratzer & Allison, 1960). Seven components were found in the blood of adult random-bred Wistar rats by CM-cellulose chromatography; their rates of synthesis appeared unaltered during erythroid cell maturation (Brada & Tobiska, 1964). A 5-component electrophoretic pattern found in some randombred Wistar rats was considered to be a combination of two 4-component patterns observed in two inbred strains (Marinkovic, Martinovic & Kanazir, 1967). A 4-component electrophoretic pattern was also reported by Cole, Hunter & Paul (1968). During gestation the number of components resolved in this buffer system increased from 1 at 13 days to 4 at 15 days; the pattern appeared identical to that of the adult from 18 days onward. Erythropoietin stimulates stem cells to mature to erythrocytes (Filmanowicz & Gurney, 1961; Orlic, Gordon & Rhodin, 1965; Nakao, Miura & Takaku, 1966). It appears to have no direct effect on haemoglobin synthesis (Erslev, 1962, 1964). In preliminary studies it was found that although erythropoietin increases the rate of haemoglobin synthesis by foetal rat liver cells in the early stages of organogenesis, it does not alter the nature of the haemoglobin produced (Cole et al. 1968). This paper presents a more complete study of haemoglobin synthesis during rat foetal development and the effects exerted by erythropoietin.