Studies of the haemopoietic microenvironments. III. Glycosaminoglycan levels in relation to phenylhydrazine-induced erythropoiesis in the mouse liver.

The possible relation between haemopoietic activity and glycosaminoglycan levels in the haemopoietic microenvironment was examined in ectopic erythropoiesis, induced by phenylhydrazine treatment, in the liver of adult mice. The hepatic glycosaminoglycan content in the liver was determined biochemically over a period of 9 d following induction of haemolytic anaemia. After induction sulphated glycosaminoglycan levels increased up to d 4, then decreased to subnormal levels on d 5 and returned to normal values on the following days. The pattern of changes in GAG content coincided with changes in the number of CFU-S and with the number of erythroblasts in the liver. This observation fits in with the hypothesis of McCuskey et al (1972) stating that high sulphated glycosaminoglycan levels are favourable for stem cell proliferation, whereas low sulphated glycosaminoglycan levels favour erythropoiesis.