PERIPHERAL PLASMA LEVELS OF OESTROGENS, PROGESTERONE AND 17α-HYDROXYPROGESTERONE DURING GESTATION IN THE RHESUS MONKEY

Abstract

Peripheral plasma levels of oestrogens¹), progesterone and 17α-hydroxyprogesterone were measured during normal pregnancy in seven rhesus monkeys. The plasma concentrations of oestrogens ranged between 200 and 1300 pg/ml throughout the gestation period. Increases in the levels of oestrogens in plasma occurred several days before parturition. The plasma concentrations of progesterone ranged between 0.5 and 22 ng/ml during pregnancy. The concentrations of oestrogens decreased dramatically after parturition and remained low during the post-partum period. The concentration of progesterone decreased after parturition, but did not reach follicular phase levels during the period observed. The plasma levels of 17α-hydroxyprogesterone were low throughout the gestation period and during the post-partum period.