HYDROXYUREA CAN BE USED TO INCREASE MOUSE C-KIT(-1.1(LO)LIN(-()THY)LO)SCA-1(+) HEMATOPOIETIC-CELL NUMBER AND FREQUENCY IN CELL-CYCLE IN-VIVO/

The DNA synthesis inhibitor hydroxyurea (HU) was administered to deter mine whether it induces changes in the cell-cycle status of primitive hematopoietic stem cells (HSCs)/progenitors. Administration of HU to m ice leads to bone marrow accumulation of c-kit(+)Thy-1.1(lo)Lin(-/lo)S ca-1(+) (KTLS) cells in S/G2/M phases of the cell cycle. HU is a relat ively nontoxic, reversible cell-cycle agent that can lead to approxima tely a threefold expansion of KTLS cells in vivo and approximately an eightfold increase in the number of KTLS cells in S/G2/M. HSCs in HU-t reated mice have undiminished multilineage long-term and short-term cl onal reconstitution activity. (C) 1997 by The American Society of Hema tology.