Expression of prolactin-related protein I at the fetomaternal interface during the implantation period in cows
Related Experiment Video
Updated: Aug 9, 2026

Mouse In Vivo Placental Targeted CRISPR Manipulation
Published on: April 14, 2023
O Yamada1, J Todoroki, K Kizaki
1Laboratory of Reproductive Biology and Technology, National Institute of Agrobiological Sciences, Ikenodai 2, Kukizaki, Inashiki Ibaraki 305-8602, Japan.
Insights
Bovine placental lactogen (bPL) and prolactin-related protein I (PRP-I) are key pregnancy hormones. This study reveals PRP-I appears early in bovine pregnancy, suggesting its role in implantation and potential as a pregnancy diagnostic marker.
Area of Science:
- Reproductive biology
- Endocrinology
- Maternal-fetal interface research
Background:
- The bovine placenta produces various molecules, notably from binucleate cells, crucial for pregnancy.
- Prolactin-related protein I (PRP-I) is a non-classical prolactin family member with an uncharacterized role during bovine implantation.
Purpose of the Study:
- To investigate the expression and localization of bovine PRP-I (bPRP-I) in the bovine placenta during early pregnancy.
- To determine the potential role of bPRP-I in trophoblast differentiation and its utility as a pregnancy diagnostic marker.
Main Methods:
- Immunohistochemistry, immunofluorescence, and in situ hybridization were employed to examine bPRP-I and bovine placental lactogen (bPL) expression.
- Tissues were collected during preimplantation (days 17-19), implantation (days 20-25), and post-implantation (days 30-60) periods.
Main Results:
- bPRP-I mRNA and protein were first detected in trophoblastic binucleate cells at day 20 of gestation, preceding bPL detection.
- By day 30 post-implantation, both bPRP-I and bPL were co-expressed in the same binucleate cells.
- bPRP-I was undetectable before implantation, suggesting a role during or after this phase.
Conclusions:
- bPRP-I expression initiates early in bovine gestation, potentially before implantation.
- bPRP-I serves as a marker for trophoblast cell differentiation.
- bPRP-I is a promising candidate for early pregnancy diagnosis in cattle.
Abstract:
The bovine placenta secretes multiple molecules during implantation and placentation, many of which are produced by binucleate cells. In this study, production of prolactin-related protein I (PRP-I), a member of the non-classical prolactin-related family, was investigated during the implantation period in cows. Expression of bovine PRP-I (bPRP-I) in the placentome was examined during the preimplantation (days 17-19), implantation (days 20-25) and post-implantation (days 30-60) periods by immunohistochemistry, immunofluorescence and in situ hybridization. During the preimplantation period, both bPRP-I and bovine placental lactogen (bPL) were undetectable in trophoblastic cells. Both bPRP-I mRNA and protein appeared first at day 20 of gestation in trophoblastic binucleate cells and multinuclear cells that might migrate into the endometrium and fuse to epithelium; however, no bPL was detected in binucleate cells at this time. After implantation, on day 30, both bPRP-I and bPL were detected in binucleate cells and were co-expressed in the same cells. These data indicate that bPRP-I may play a role before implantation and that bPRP-I may be an excellent marker for trophoblastic cell differentiation, as well as a candidate for pregnancy diagnosis.
Related Concept Videos
Transcytosis of IgG
IgG molecules from a mother undergo transcytosis starting around 13 weeks of gestation. The amount of IgG transferred and entering the fetal blood circulation increases with...
Ovarian Cycle

