Bioassay for Thrombopoietin Utilizing Mice in Rebound Thrombocytosis 1

Abstract

Summary

A bioassay for the detection of the thrombopoietic stimulating factor (TSF or thrombopoietin) that utilizes thrombo–cythemic mice has been presented. A single injection of anti–mouse platelet serum (AMPS) to mice produced a characteristic thrombocytopenia that was followed by rebound thrombocytosis. Two to three days later (7–8 days after the AMPS injection), a significantly (p < 0.05) depressed thrombo–poiesis existed in response to the thrombocytosis. Normal and thrombocythemic mice were injected with normal sheep sera or sera from platelet–depleted sheep and Na₂ ³⁵SO₄ incorporation into platelets was measured. A greater difference in ³⁵S uptake existed between AMPS–treated control mice (mice injected with normal sheep serum) and AMPS–treated stimulated mice (mice injected with serum from platelet–depleted sheep) than in normal mice treated with the same sera. Also, TSF in sheep sera was shown to lose activity after storage at −20°.

The author is grateful to Mrs. Marilyn Cottrell and Miss Rose Clift for technical assistance and to Mrs. Ann Beardsley for her art and stenographic services. Appreciation is also extended to Mr. George Creswell for help in bleeding and maintaining the sheep, to Mr. James Dyer for help in performing the mouse assays, and to Dr. T. T. Odell, Jr. and Dr. Shirley Ebbe for their many helpful suggestions.