To determine whether prostaglandin (PG) F2α had a dose-dependent effect upon secretion of progesterone, oligonucleosome formation, or loss of luteal weight, ewes on Day 9 or 10 of the estrous cycle were administered 0, 3, 10, or 30 mg PGF2α per 60 kg BW (i.v.), and luteal tissue was collected 9 and 24 h after injection. All doses of PGF2α decreased (P < 0.05) concentrations of progesterone in sera by 9 h; however, in ewes treated with 3 mg PGF2α, concentrations of progesterone were similar to control values at 24 h and higher (P < 0.05) than those in the 10- or 30-mg groups. Concentrations of progesterone in sera over all dose levels were highly correlated to luteal concentrations of mRNA encoding steroidogenic acute regulatory protein (P < 0.001), cytochrome P450 side-chain cleavage (P < 0.02), and 3β-hydroxysteroid dehydrogenase (P < 0.01). Corpora lutea collected at 24 h from ewes treated with the 10- and 30-mg doses of PGF2α weighed less (P < 0.05) than those from controls. Oligonucleosomes were not present in luteal tissues from control ewes. Surprisingly, all doses of PGF2α-induced oligonucleosomes in a majority of animals at 9 h and in a majority of ewes treated with 10 and 30 mg of PGF2α at 24 h. In conclusion, 3 mg of PGF2α per 60 kg BW transiently decreased serum concentrations of progesterone and induced oligonucleosome formation, but did not result in reduced luteal weight. The 10- and 30-mg doses of PGF2α decreased secretion of progesterone and induced oligonucleosome formation and luteolysis.
How to translate text using browser tools
1 April 2000
Effect of Dose of Prostaglandin F2α on Steroidogenic Components and Oligonucleosomes in Ovine Luteal Tissue
J. L. Juengel,
J. D. Haworth,
M. K. Rollyson,
P. J. Silva,
H. R. Sawyer,
G. D. Niswender
ACCESS THE FULL ARTICLE