Studies of prostaglandin F 2α in the cow

Abstract

PGF 2α was administered into the lumen of the uterus, into the uterine artery or into the jugular vein, of pregnant cows and cows in the luteal phase of estrous cycle. Plasma concentrations of PGF 2α, progestins, and estrogens were determined. Peripheral plasma levels of PGF 2α had returned to normal within 10 minutes after i.v. injection. After intraluminal administration the concentration in uterine venous plasma was elevated for about 15 minutes. All methods of administration caused an initial increase in progesterone secretion, but within one day, luteolysis had occurred, thus resulting in abortion or reduction in the length of the estrous cycle. PGF 2α was luteolytic when given intraluminally to cows in which the A. ovarica was sectioned and the blood supply to the ovary was via an alternate route (an anastomosis between the uterine artery and the uterine branch of the ovarian artery). PGF 2α did not cause uterine contraction as has been observed in the woman. Intrauterine administration of prostaglandin F 2α (PGF 2α) causes uterine contractions in the human, and luteolysis in many species including the ewe, cow, and mare. In order to evaluate the potential role of PGF 2α as a tool in veterinary medicine the compound was administered to cows during early pregnancy or during the luteal phase of the estrous cycle. The compound was injected into the jugular vein, the lumen of the uterus or the uterine artery. Blood was collected from the jugular vein as well as the veins draining the uterus and ovary in order to determine changes in concentrations of PGF 2α, progesterone, and total estrogens.