Effects of Different Routes of Administration and Injection Schedules of Thrombopoietin on 35 S Incorporation into Platelets of Assay Mice 1

Abstract

Summary

The 24-hr percentage of ³⁵S incorporation into platelets of mice in rebound thrombocytosis was compared after single or multiple sc and ip injections of a thrombopoietin (TSF)-rich preparation. TSF administered sc or ip resulted in almost identical percentage of ³⁵S incorporation values. Various doses of TSF injected sc two times on Day 5 after RAMPS and two times again on Day 6 gave a linear dose-response curve. Also, this injection schedule gave the greatest response to the same total dose of TSF when compared to other injection schedules. Single injections of TSF did not give as great a response as did multiple injections using the same total dose. Results of this work indicate that for maximum percentage of ³⁵S incorporation values, TSF-rich materials should be administered in multiple injections to mice, either sc or ip, over a period of approximately 2 days.

The author thanks Rose Clift and Marilyn Cottrell for technical assistance, Patricia Wayne for stenographic and art work, and Otto Walasek, Abbott Laboratories, North Chicago, Illinois, for supplying the TSF-rich kidney cell culture medium.