Discordant secretion of pregnancy specific β1-glycoprotein and human chorionic gonadotropin by human pre-embryos cultured in vitro

Abstract

To study and compare the secretion of pregnancy specific beta 1-glycoprotein (SP1) and human chorionic gonadotropin (hCG) by human pre-embryos, cultured in vitro, with their respective morphological development. Spare human pre-embryos from randomly selected women participating in a program of in vitro fertilization (IVF) were studied prospectively. Pre-embryos were cultured, and hormone release was determined in academic research laboratories. Pre-embryos (n = 108) cultured for 14 days after fertilization in Ham's F-10 medium (GIBCO Ltd., Paisley, Scotland) were observed, and hCG and SP1 were measured in the culture media at regular intervals. Discordant secretion of SP1 and hCG. Of the 98 bipronucleate pre-embryos, 53.6% formed blastocysts, 17.3% of which hatched. Human chorionic gonadotropin was detected from day 7 after fertilization concomitantly with blastocyst formation, thereafter showing a logarithmic increase (maximum 10,650 mIU) until the first signs of embryonic disintegration. Pregnancy-specific beta 1-glycoprotein release started 3 to 4 days after fertilization independently of the morphological development and the future production of hCG, thereafter displaying a nonlogarithmic increase (maximum 41 ng). Hormone secretion and morphological development are unique for each pre-embryo. Human chorionic gonadotropin and SP1 seem to have different biochemical and physiological regulation.