PROSTAGLANDIN DYNAMICS ASSOCIATED WITH DEVELOPMENT OF THE BOVINE CONCEPTUS
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
Oestradiol injection induces an acute increase in uterine production of PGF2 that can be monitored in the peripheral circulation of cattle by measurements of 15-keto-13,14-dihydro-PGF2 (PGFM). Spikes of PGFM were detected prior to luteolysis. An oestradiol induced increase in PGFM concentrations is reduced in pregnant cows at days 18 and 20 compared to day 18 cyclic cows. Evidence is presented that supports a local venoarterial pathway for exchange of PGF2 from the uterus to the ovary. Lower concentrations of PGF2 in the ovarian artery of pregnant cows also are consistent with a conceptus induced antiluteolytic effect. Endometrial tissues from day 17 pregnant cows synthesized, in vitro, less PGF2 than day 17 cyclic cows. Tissues from uterine endometrium, ovarian vein and ovarian artery of day 17 pregnant cows also accumulated less PGF2, in vitro, than day 17 cyclic cows. Pregnancy at 17 days does not appear to influence transport of exogenously administered PGF2 from the uterine lumen. Such agents as oestradiol and PGE2 enhance PGF2 movement from the uterine lumen. The early pregnant cow appears to have a diminished endometrial secretion of PGF2 that favors luteal maintenance. Conceptus induced alterations in tissue permeability and conceptus control of delivery systems from the uterus also may influence balance of luteolytic and luteotrophic substances delivered to the ovary for luteal maintenance. 1984.