Localization of the GnRH and its mRNA was performed in the human placentas by immunohistochemistry and in situ hybridization techniques. Human placentas in first, second, and third trimester of normal pregnancy were obtained. These placentas were
fixed
with 4% paraformaldehyde and embedded in OCT compund, and sectioned by cryostat. For immunohistochemical study, avidin-biotin peroxidase complex(ABC) method and immunofluorescence method were employed and for in situ hybridization histochemistry
digoxigenin-dCTP labeled cDNA and 35S labeled RNA probes were used and followed by autoradiography.
GnRH and its mRNA were localized in the cytotrophoblast, syncytiotrophoblast, and villous stromal cells of the human placental villi. The distribution and intensity in GnRH immunohistochemistry were showed to be similar to those in GnRH mRNA in
situ
hybridization histochemistry. GnRH immunoreactivity and its mRNA signals were identified nearly constantly in both the cytotrophoblast and syncytiotrophoblast cells throughout gestation. However, those in the villous stromal cells were shown to
be
gradually increased with placental development, although not in the cells of early placenta. These results suggest that the local GnRH or GnRH-like substance may be synthesized in the human placental villi and may, thus, represent a loca 1
paracrine or
autocrine role in endocrine control mechanism within the placenta.
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