Chorionic Gonadotropin, Estradiol, and Progesterone Levels in Baboons (Papio Anubis) during Early Pregnancy and Spontaneous Abortion1

Abstract

The purpose of this study was to sequentially characterize peripheral chorionic gonadotropin (CG), estradiol (E2), and progesterone (P) profiles during early pregnancy in the baboon (Papio anubis). Ten pregnant baboons were bled sequentially at eighteen time points between Days 8 and 128 of gestation. In addition, blood was obtained at corresponding time points from 5 spontaneously aborting baboons. CG levels were assessed in a mouse Leydig cell bioassay using rhesus pituitary LH as the standard E2 and P levels were measured by RIA. Pregnancy-associated CG activity was detectable by Day 15 (901.4 +/- 275.6 ng/ml), peaked at Day 27 (53,494.1 +/- 14,995.6 ng/ml), and then returned to baseline values by Day 51 (45.4 +/- 8.9 ng/ml). Mean E2 concentrations rose from 28.9 +/- 4.3 pg/ml on Day 8 to 280.6 +/- 145.5 pg/ml on Day 58 and then increased 9-fold to a level of 2436.4 +/- 928.0 pg/ml on Day 72. Mean E2 concentrations ranged between 2065.9 and 3830.9 pg/ml from Day 72 through Day 128. Mean P concentrations ranged from 7.5 to 10.2 ng/ml between Days 8 and 21, rising dramatically to 38.6 +/- 4.6 ng/ml on Day 37 prior to declining to levels that ranged from 11.1 to 17.1 ng/ml between Days 51 and 128. CG levels were low in 3 of 5 animals prior to spontaneous abortion E2 and P concentrations preceding spontaneous abortion were similar to values in uncomplicated pregnancy; however, at the time abortion was detected P concentrations in all 5 animals were 1.3 ng/ml or less.(ABSTRACT TRUNCATED AT 250 WORDS)