Release of prostaglandin F2 alpha during the oestrous cycle
Kindahl, H.; Lindell, J.O.; Edqvist, L.E.
Acta Veterinaria Scandinavica. Supplementum 77: 143-158
1981
ISSN/ISBN: 0065-1699 PMID: 7030023 Document Number: 171552
To evaluate the role of progesterone for regulating the prostaglandin biosynthesis the following experiments were conducted in non-pregnant cattle: (1) enucleation of the corpus luteum at different stages of the oestrous cycle; (2) injections of cloprostenol at different stages of the oestrous cycle; and (3) progesterone implants inserted during the oestrous cycle. Experiments (1) and (2) showed that early in the cycle there was no release of PGF2 alpha in conjunction with progesterone withdrawal, whereas after about day 12-13, a small and short-lasting release of PGF2 alpha could been seen. Experiment 3 showed clearly that the duration of the luteolytic PGF2 alpha release is dependent on circulatory levels of progesterone above a low and critical level once the PGF2 alpha release has been initiated.