PLACENTAL TOXIN: INACTIVATION AND TOLERANCE DURING PREGNANCY

Abstract

Toxic placental extracts were inactivated by blood. The inactivating potency remained with the globulin fraction. The level of inactivator in serum of [male][male] and of non-pregnant [female][female] was approx. 40 [mu]/ml. The titre of inactivator increased 6 times during human pregnancy and 21 /2 times during mouse pregnancy. Despite the increase of inactivator during pregnancy, mice became much more sensitive to the toxin during pregnancy, not only per g. of body wt. but also per whole mouse. Hence, it was suggested that a product of the reaction between toxin and inactivator was in some way a step in the response of the animals to the toxin. Pregnant mice were more difficult to desensitize than were non-pregnant mice. During the desensitization (refractory state) of a few hrs. duration, massive doses of toxin could be administered. Subsequent focal liver necrosis and occasional kidney lesions followed these massive doses in the same manner as with non-pregnant mice; in addition, the pregnant mice commonly aborted.