Type II and type IIB activin receptors in human placenta.

Abstract The expression of type II activin receptor(ActRII) and type IIB activin receptor(ActRIIB) messenger RNA(mRNA) in different stages of development of the human placenta was examined by Northern blot analysis. In our experiments, the first trimester placenta showed the highest levels of ActRIIB expression and human placenta from different stages expressed both type II and IIB activin receptor mRNAs. These observations support the hypothesis that activin might act as a paracrine/autocrine factor in human placenta and activin might have stage specific functions through the different types of receptors.