Spontaneous, Gonadotropin-Releasing Hormone-Induced, and Progesterone-Inhibited Pulsatile Secretion of Human Chorionic Gonadotropin in the First Trimester Placenta in Vitro

Using a multichannel superfusion apparatus, the secretion of human chorionic gonadotropin (hCG) was measured at 1-6 minute intervals in placental explants at 7-9 weeks of gestation. hCG was found to be secreted in distinct pulses (4-5 fold above baseline) every 11-23 minutes peak to peak. Addition of one minute pulses of GnRH analog significantly increased, whereas pulses of progesterone decreased, pulsatile hCG secretion.