Incorporation of BrdU by BM granuloctyes and its persistence after ingestion has stopped.

(A) BrdU incorporation by BM granulocytes following prolonged administration of BrdU in vivo. BM granulocytes were isolated from chronically BrdU-fed animal at different time points and analyzed for their BrdU incorporation flow-cytometrically by means of an anti-BrdU mAb conjugated with FITC and PI. The open circles indicate data obtained from one unperturbed animal (PA6588); the closed squares indicate data from a second baboon (PA6589). (B) Persistence of BrdU⁺ granulocytes following the cessation of BrdU ingestion. Granulocytes were isolated from one of the animals who had been continuously fed BrdU for 52 weeks, and the percentage of BrdU⁺ granulocytes on the day of cessation of BrdU feeding is indicated as Day-0. Samples were obtained 20 days and 159 days after withdrawal of BrdU. Granulocytes from both of these samples were isolated and analyzed for their BrdU content. The bars represent the percentage of granulocytes that were BrdU⁺ on the day BrdU feeding was halted, as well as 20 days and 159 days after withdrawal of BrdU.