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Pregnancy-associated plasma protein-A (PAPP-A) is a 200 kDa metalloprotease identified as an IGFBP-4 protease and likely an important regulator of IGF bioavailability. PAPPA mRNA is detected in bovine granulosa and theca cells and the PAPP-A protein is also found in follicular fluid. Proteolytic activity supposed to be due to the PAPP-A in bovine follicular fluid is induced by follicle stimulating hormone (FSH) treatment and PAPP-A-like activity appears concomitantly with increased E2 during follicular development. However, the effects of FSH, E2 and progesterone on the expression of PAPP-A in bovine corpus luteum of pregnancy have been evaluated in a limited number of studies. This study was performed to expression of PAPP-A and progesterone during early pregnancy in bovine corpus luteum. To determine the function of PAPP-A gene during early pregnancy, we collected the bovine pregnancy corpus luteum samples on 30, 60 and 90 day of pregnancy. The mRNA expression of PAPP-A, progesterone-receptor, VEGF and IGFBP4 gene was conducted by real-time PCR. And proteins expression of PAPP-A and progesterone antibody was detected by Immunohistochemistry and ELISA. The VEGF and PAPP-A mRNA expression was progressively increased on day 90 in the pregnancy corpus luteum. The mRNA expression of progesterone-receptor, IGFBP4 in the corpus luteum progressively was increased from 30 to 60 day, but decreased on 90 day of pregnancy. The proteins expressions of progesterone and PAPP-A were similar pattern in mRNA expression. Our results indicate that the IGFBP4 protease role of PAPP-A increases in response to pregnancy 90 day corpus luteum and suggest that progesterone is an connected for the expression of PAPP-A genes in luteal cells. Therefore, we suggest that PAPP-A stimulated with progesterone play a crucial role for IGF-I system in bovine early pregnancy. And could be used to predict the condition of normal pregnancy.
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