Effect of aminoglutethimide on serum progesterone and estrogen in the pregnant baboon (Papio SP).

AG was administered orally twice daily for 1 or 3 days to six baboons whose duration of pregnancy ranged from 31 to 99 days. Serum progesterone levels were reduced to as little as 3.2% of the initial concentration in one animal and to 20% or less in four of the five remaining baboons. Serum estrogen levels were depressed by 50% or more in three of the four animals in which they were measured. However, pregnancy ensued for at least 3 wk after treatment in all animals. The data suggest that peripheral blood levels of sex steroids may not reflect the critical concentration of hormones required at the uteroplacental juncture for the successful pregnancy maintenance.