Effects of salicylate and other enhancers on rectal absorption of erythropoietin in rats.

To develop a new treatment for patients with anaemia in which erythropoietin (EPO) can be given without injection, the effects of promoters of the rectal absorption of EPO were studied. Recombinant human (rHu) EPO (5000 units) in a dosing solution or in a rectal suppository was placed in the rectum of healthy rats and changes in serum EPO levels were monitored by an enzyme-linked immunosorbent assay. Without a promoter, rHuEPO was not absorbed.

Effects of site-directed removal of N-glycosylation sites in human erythropoietin on its production and biological properties.

Erythropoietin (Epo) has three N-linked sugar chains. Codons for asparagine at N-glycosylation sites in genomic human Epo DNA were replaced with those for glutamine. The wild-type Epo gene and seven mutants that lacked N-glycosylation sites in every possible combination were introduced into baby hamster-kidney cells.

Factor with erythroid burst-promoting activity in human urine unlike other hematopoietic growth factors.

A factor with burst-promoting activity (BPA) stimulates the formation of erythroid bursts in the presence of erythropoietin, acting on early erythroid progenitor cells (erythroid burst-forming units, or BFU-E). Here we investigated the biological properties of this factor partially purified from the urine of anemic patients. The human urinary factor did not cause the formation of late erythroid progenitor cells (erythroid colony-forming units, or CFU-E) or enhance such colony formation in the presence of erythropoietin.

Renal anemia in polycystic kidney disease mouse.

DBA/2FG-pcy mice developed the chronic renal failure by the progressive polycystic formation at five months old. Their bilaterally enlarged kidneys occupied about 15% of the body weight. It was about 9 times larger than the normal kidney of DBA/2N mice.