TOXICITY OF SALINE UTERINE EXTRACTS FROM RABBITS DURING PREGNANCY, PSEUDOPREGNANCY AND AFTER CORPUS LUTEUM HORMONE ADMINISTRATION1

Abstract

Crude saline extracts of preg nant rabbit uteri are fatally toxic when injected intraven. into animals of the same sp., while similar uterine extracts from non-pregnant rabbits are not. The toxic factor appears in the pregnant uterus 2 days post-coitum and persists throughout the gestation period. Extracts prepared from uteri in the last 3d of gestation contain less of the toxic substance than similar extracts of uteri from earlier in pregnancy. The toxic substance is also present in uteri during pseudopregnancy, appearing as early as 24 hrs. after induction of pseudopregnancy and persisting until approx. the 17th day. These findings suggest a temporal relation between the presence of the toxic substance and the presence of functional corpora lutea. Furthermore, saline extracts of uteri from ovariectomized, corpus luteum hormone treated rabbits are extremely toxic indicating that the hormone of the corpus luteum may be involved in the production or accumulation of the toxic material.