Submitted to: Biology of Reproduction Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: April 19, 1996
Publication Date: N/A
Cortisol affects late fetal development in many species, including swine. To investigate cortisol involvement during early gestation, a study was conducted to determine if cortisol and its extracellular binding protein CBG are present in the porcine uterine environment during early pregnancy and the estrous cycle. After slaughter on days 7, 10, 13, 16, and 19 of pregnancy and days 7, 10, 13, and 16 of the estrous cycle (n = 4-7 gilts/ day), uterine horns from each gilt were flushed with 20 ml of Eagle's MEM. There were no differences in uterine flushing cortisol (UF-C) content between pregnant and cyclic gilts (p >/- .14). In both groups, UF-C was constant between days 7 and 13. Subsequently, UF-C increased threefold (p<.01) in pregnant gilts (14.5 +/- 5.7 vs 61.9 +/- 24.4 ng/uterus) between days 13 and 19 and almost sevenfold (p<.01) in cyclic gilts (13.4 +/- 6.3 vs 103.3 +/- 40.6) between days 13 and 16. Uterine flushing CBG (UF-CBG) content in cyclic gilts exceeded (p<.01) that in pregnant gilts only on da 10. In both groups, UF-CBG was constant between days 7 and 10. However, UF-CBG then increased (p<.01) 87-fold in pregnant (.08 +/- .05 vs 7.07 +/- 5.2 ug/uterus) and 70-fold (.34 +/- .25 vs 24.12 +/- 17.90) in cyclic gilts between days 10 and 16. In pregnant gilts, UF-CBG did not change between days 16 and 19. Therefore, conceptuses did not influence the presence, timing, or magnitude of uterine cortisol increases but were associated with modest decreases in UF-CBG on day 10. Increased uterine cortisol could influence either uterine function or embryonic development. Dramatic increases in UF-CBG strongly suggest a biological function for intrauterine CBG. As CBG binds both cortisol and progesterone, it could serve to modulate intrauterine actions of either steroid.