title: Evaluation of beta-endorphin and naloxone on bovine uterine motility.
abstract: Effects of beta-endorphin and naloxone on bovine uterine motility were tested both in vivo and in vitro. Six cyclic Holstein cows were used to study in vivo effects of beta-endorphin and naloxone on uterine motility during estrus and diestrus. Intrauterine pressure changes were recorded by a microtip pressure transducer before and after treatment. Blood samples were taken every 10 min during the recording periods for beta-endorphin assay. The results revealed that beta-endorphin anc naloxone had no effect on intrauterine pressure in vivo. The effects of beta-endorphin and naloxone on myometrial contractility were also examined in vitro. Beta-endorphin and naloxone were added to tissue baths containing estrous and diestrous uterine strips. The results showed no significant effect of beta-endorphin and naloxone on bovine myometrial contractility. The role of beta-endorphin in bovine reproductive physiology is still not clearly understood, and additional studies are needed.
authors.affiliation: Department of Veterinary Clinical Medicine College of Veterinary Medicine University of Illinois Urbana, IL 61801 USA.
authors.forename: C H
authors.initials: CH
authors.lastname: Ko
authors.forename: L G
authors.initials: LG
authors.lastname: Wheaton
authors.forename: D J
authors.initials: DJ
authors.lastname: McKenna
authors.forename: H L
authors.initials: HL
authors.lastname: Whitmore
authors.forename: B K
authors.initials: BK
authors.lastname: Gustafsson
authors.forename: R P
authors.initials: RP
authors.lastname: Smith