Ml. Brizot et al., PLACENTAL EXPRESSION OF ALPHA-SUBUNITS AND BETA-SUBUNITS OF HUMAN CHORIONIC-GONADOTROPIN IN EARLY PREGNANCIES WITH DOWNS-SYNDROME, Human reproduction, 10(9), 1995, pp. 2506-2509
This study examines the expression of alpha and beta subunits of human
chorionic gonadotrophin (HCG) in samples of placental and decidual ti
ssue obtained at 11-15 weeks of gestation from 30 control pregnancies
and 11 pregnancies with trisomy 21. In the placental tissue, the conce
ntrations of beta-HCG mRNA and alpha-HCG mRNA were augmented in six an
d seven of the trisomy 21 cases respectively and in 16 and 14 of the c
ontrol pregnancies. The median values of beta-HCG mRNA and alpha-HCG m
RNA in the two groups were not significantly different. Although the m
edian serum free beta-HCG concentration was significantly (P = 0.03) h
igher in trisomy 21 pregnancies than the controls, there was no relati
onship between serum free beta-HCG and relative abundance of beta-HCG
mRNA in either the trisomy 21 pregnancies or the controls. Decidual ex
pression of beta-HCG and alpha-HCG mRNA were below detection level in
the Northern blot analysis in both the trisomy 21 pregnancies and the
controls. These findings suggest that the increase in maternal serum f
ree beta-HCG concentration in trisomy 21 pregnancies occurs during the
post-transcriptional phase of HCG protein biosynthesis.