Progesterone and 15-keto-13, 14-dihydroprostaglandin F2alpha levels in peripheral circulation after intrauterine iodine infusions in cows
Kindahl, H.; Granström, E.; Edqvist, L.E.; Gustafsson, B.; Aström, G.; Stabenfeldt, G.
Acta Veterinaria Scandinavica 18(2): 274-286
1977
ISSN/ISBN: 0044-605X PMID: 560113 Document Number: 124144
The effect of intrauterine iodine infusion on oestrous cycle length was studied in four cows. The infusions were performed at various times of the oestrous cycle: early, middle, late, and during luteolysis. Blood samples were drawn every third hour from the jugular vein. Progesterone and 15-keto-13,14-dihydroprostaglandin F2 alpha (the main metabolite of PGF2 alpha ) were measured to monitor luteal activity and prostaglandin release. No release of prostaglandins was observed immediately after intrauterine infusion. Infusion in two cows on day 5 of the oestrous cycle resulted in prostaglandin release after 54 and 69 hours, respectively, followed by luteal regression and the occurrence of oestrus at approx. five days after infusion. Infusions performed on days 11 or 12 resulted in prostaglandin release after 147 and 120 hours, respectively, followed by luteolysis and heat after a 19 day oestrous cycle. Infusion in two cows at days 16 and 17 resulted in prostaglandin release after 117 hours in both animals. One cycle was prolonged whereas the other cycle was normal in duration. One cow infused on day 20 following the occurrence of the first prostaglandin surge had a cycle length of 26 days, whereas another cow infused on day 20 was not affected because luteolysis was essentially complete by the time of infusion. One animal infused on day 5 did not respond to the iodine infusion. In this animal, however, the corpus luteum was not completely developed prior to the infusion. From this study it can be concluded intrauterine iodine infusions performed after the development of a progesterone secreting corpus luteum result in prostaglandin release within three to six days with the subsequent occurrence of luteolysis and that luteolysis was in all cases observed in connexion with prostaglandin F2 alpha release of the same order of magnitude and duration as during normal luteolysis.