Inactivation of Antidiuretic Hormone by Blood Serum of the Pregnant Woman. ∗

Abstract

Summary

The “antidiuretasic activity” (activity responsible for the destruction of the antidiuretic properties of vasopressin) of the blood sera increases progressively in the course of pregnancy. In the last week of pregnancy 0.1 ml of blood serum destroys 300 to 350 mU of vasopressin in 40 to 50 minutes, whereas in the nonpregnant woman it inactivates only 30 to 35 mU in 960 minutes. The “anti-diuretasic activity” rapidly decreases in the post-partum period and reaches the values preceding pregnancy after 5 or 6 days of delivery.