Estrogen reduces mitotic activity of B cell precursors.

BALB/c and RAG-2^−/− mice were given hormone implants and BrdU (1 mg/mL +5% glucose) was administered in the drinking water for the last 3 days of treatment. CD45R⁺cells were then analyzed with respect to size (forward angle light scatter) versus BrdU uptake. The data are representative of results obtained with 5 control and 8 estrogen-treated BALB/c and 3 control and 3 estrogen-treated RAG-2^−/− mice.