Intercalating substances do not induce sister-chromatid exchanges (SCEs) in vivo.

In contrast to findings in vitro, the intercalating substances proflavine, methylene blue and chlorpromazine did not induce sister-chromatid exchanges (SCEs) in the SCE test in vivo in the bone marrow of the Chinese hamster. The distribution of the metaphases of the first, second and third replication cycles in the presence of bromodeoxyuridine (BrdUrd) showed all 3 substances to have no inhibitory effect on the cellular proliferation in the bone marrow.