Potentiation of Purified Erythropoietin with Serum Proteins. II: Serial Dose Response Relationships.∗

Summary Erythropoietin (urinary fraction II + III) was diluted with either saline or normal serum and injected into assay animals as a single dose or as 2 or 4 fractional doses either intraperitoneally or subcutaneously. Erythropoietic activity increased as the dose was fractionated; however, the erythropoietin plus serum showed greater activity than erythropoietin plus saline in all dosage schedules. This suggests that normal serum actually enhances the activity of erythropoietin rather than merely acting as an adjuvant causing delayed absorption of the material. Grateful acknowledgement is made to Miss Bettie Williams and Mrs. Carol Cope for fine technical assistance, to Dr. Charles B. Bragassa, Mrs. Rebecca Bedingfield and Mr. Bob Ellis of the Computer Center, Medical College of Georgia, for statistical analyses and to Mrs. Margaret Hiers and Mrs. Shirl Melton for secretarial assistance.