Effects on Parturition in the Rat of Ablation of Different Lobes of the Hypophysis.

Abstract

Ablation of the posterior and intermediate lobes of the hypophysis either before conception, or on the 12th day of gestation, resulted in no disturbances in duration of pregnancy, in parturition, or in onset of lactation. Removal of the anterior lobe of the hypophysis had the same effects on pregnancy and parturition as did total hypophysectomy. After both types of operation 25% of the rats delivered normally at term; 75% had a prolonged pregnancy (1-3 days) and either delivered late, resorbed, or died in an effort to deliver. Terra-mycin injns. given to 27 rats on the 1st and 2d days following hypophysectomy decreased postoperative mortality and resulted in a larger percentage of normal deliveries and in a smaller fatality rate at parturition as compared with 30 non-injd. animals.