Submitted to: Biology of Reproduction Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 23, 1997
Publication Date: N/A
Technical Abstract: The objectives of these experiments were to (1) confirm that folate binding capacity of uterine flushings increases in cyclic and pregnant gilts from days 10 to 15 and (2) clone an FBP cDNA and analyze endometrial FBP mRNA. Uterine flushings and endometrium were obtained at slaughter on days 10, 11, 12, 13, and 15 of the cycle or pregnancy and further endometrial tissue esamples were obtained on days 24, 30 and 40 of pregnancy. Uterine flushing were incubated with 3H-folate +/- excess unlabelled folate and bound and free 3H-folate were separated. Mean total specific binding of folate increased (p<0.01) from 15 to 2,142 pmol/uterine flush (n=8 and 9, respectively) from day 10 to day 15 and did not differ between cyclic and pregnant gilts. Using day 30 pregnant endometrial RNA, reverse transcription followed by polymerase chain reaction with primers designed from mouse folate receptor (FR) beta cDNA resulted in a partial cDNA for porcine FBP of 473 bp which was subcloned and sequenced. The cDNA sequenc was homologous to other known FR and appeared to code for putative amino acids 38 to 195 of FBP. Homology of the deduced amino acid sequence with other known FBP/FR ranged from 76% (mouse FR beta) to 90% (bovine milk FBP). Northern analysis of endometrial RNA from days 10 to 40 indicated that mRNA levels for FBP did not change from day 10 to 15 of the cycle or pregnancy, increased by day 24 of pregnancy and remained high on day 30 and 40. These results confirm that FBP increases in the intrauterine lumen between day 10 and 15 of the cycle and pregnancy in the absence of changes in endometrial FBP mRNA concentrations. However, the mRNA for FBP did increase by day 24 of pregnancy. These results suggest that FBP plays a role in transport of folate to the developing conceptus.