Yolk sac-derived rat teratomas are not of germ cell origin

In an attempt to verify the possibility that yolk sac-derived rat teratomas may be of germ cell origin, pregnant rats were treated with Busulphan. This drug, which is known to destroy the germ cells during their migratory phase, led to the complete absence of these cells in the gonads. However, Busulphan did not influence the number or the morphology of the yolk sacderived teratomas. Therefore it is concluded that these teratomas do not arise from germ cells.