Effects of Administration of Prostagrandin F2.ALPHA.-Analogue Fenprostalene on Canine Corpus Luteum and Subsequent Recurrence of Estrus and Fecundity.

Abstract

ABSTRACT. The effects of the long-acting prostagrandin F 2α -analogue fenprostalene were investigated. Twenty-three female beagles (24 cases) 1-6 years of age were divided into 6 groups, and a dose of 5-150 µg/head of fenprostalene was subcutaneously administered at 25 days after ovulation to investigate its effects based on peripheral blood progesterone (P 4 ) levels. The dogs were also examined for shortening of their estrous cycle after administration and fecundity after the recurrence of estrus. The results showed that the administration of 50 µg/head of fenprostalene or more reduced the levels of peripheral blood P 4 to about 1 ng/ml 2 days after administration, indicating early regression of the corpus luteum, and that the administration of these doses shortened the time to the subsequent estrus by a mean of about 80 days, and that conception rates were normal if estrus recurred about 2 months after fenprostalene administration or later.

Using PGFM (13,14-dihydro-15-keto-prostaglandin F2α) as a non-invasive pregnancy marker for felids

“…PGF 2␣ is a prostaglandin, that has been portrayed as a locally bioactive hormone detectable in virtually all tissues [15]. It is now widely accepted that uterine and placental prostaglandins play a key role in regulating the function and life span of corpora lutea [16] and exogenous PGF␣ is luteolytic in both pregnant and pseudo-pregnant bitches [17]. Serum PGFM analyses in the dog revealed different patterns between pregnant and non-pregnant (diestrus) bitches [18].…”

Fenprostalene-induced Abortion in Bitches.

“…The duration of the period after fenprostalene administration to the next estrus in the non-fertilized dogs was significantly shortened to 46.2 ± 15.8 days. In our previous study, among bitches treated with fenprostalene during the luteal phase, dogs with estrus about 2 months or more after administration became pregnant [5]. However, among dogs treated with fenprostalene during pregnancy, some bitches with estrus 80 or 98 days after administration were infertile.…”

“…We previously investigated the influence of fenprostalene (BOVILENE ® Syntex Animal Health, Inc.), which is a PGF 2α analogue with prolonged activity, on estrus/luteal functions in beagles [5]. Administration of 50 µg or more of fenprostalene 25 days after ovulation (during the luteal phase) decreased peripheral blood P 4 levels to the baseline (approximately 1 ng/ml) 2 days after administration regardless of the dose, and early luteal regression was achieved.…”

Pituitary Hormone Responses to Luteal Regression after Administration of Prostaglandin F2α‐Analogue

“…PGF-F was administered at 24 days after ovulation when the corpus luteum exhibited maximal activity and at 54 days after ovulation when the corpus luteum was regressing. The dose of PGF-F that induced luteal regression was 50 lg/head during the early phase as we previously reported (Hori et al 2002), and was administered once subcutaneously to 10 dogs each on days 24 and 54. As a control, physiological saline was administered to three dogs each on days 24 and 54, a total of six dogs (control group).…”