Effect of systemic intravenous infusion of PGF-2  and 13,14-dihydro-15-keto-PGF-2  on the release of oxytocin-associated neurophysin from the ovary in the ewe

Watkins, W. B.; Moore, L. G.

doi:10.1530/jrf.0.0800105

Cited by 16 publications

(4 citation statements)

References 25 publications

(37 reference statements)

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“…The finding that exogenous PGF-2u will cause release of oxytocin (Flint 8c Sheldrick, 1982;Lamsa et ai, 1989) and measurement of concomitant pulses of PGF-2a and oxytocin during luteo¬ lysis (Fairclough et ai, 1980(Fairclough et ai, ,1983Flint & Sheldrick, 1983;Vighio & Liptrap, 1986) led Flint et ai (1986) to conclude that an essential aspect of luteal regression was participation by oxytocin and PGF-2a in a positive feedback loop. An infusion of PGFM caused release of oxytocin-associated neurophysin from CL in cyclic ewes (Watkins & Moore, 1987). Addition of oxytocin to uterine endometrium collected from post-partum cows resulted in the release of PGFM in vitro (Del Vecchio et ai, 1988).…”

Section: Discussionmentioning

confidence: 99%

Effects of progestagen treatment on concentrations of prostaglandins and oxytocin in plasma from the posterior vena cava of post-partum beef cows

Cooper¹,

Carver²,

Villeneuve³

et al. 1991

Reproduction

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The role of PGF-2 alpha in determining the lifespan of corpora lutea in the post-partum beef cow was investigated. In control cows (N = 5) induced to ovulate at Day 28 to 36 post partum by injection of 1000 i.u. hCG, corpora lutea had an average lifespan of only 8 days. In cows pretreated with 6 mg implants of a progestagen (norgestomet, N = 4) for 9 days, with implant removal 2 days before injection of hCG, luteal lifespan averaged 17.5 days. Concentrations of PGF-2 alpha in 9 hourly samples of plasma collected from the posterior vena cava via indwelling catheters were higher on Days 4 through 9 after injection of hCG (P less than 0.05) in the cows with short-lived corpora lutea. Greater release of PGF-2 alpha could therefore be a major factor in premature luteal regression. Concentrations of PGFM and oxytocin did not differ between cows with corpora lutea of short or normal lifespan. In a second experiment, concentrations of PGF-2 alpha in plasma from the posterior vena cava were examined during treatment with norgestomet (N = 8) or in contemporary controls (N = 7). In progestagen-treated cows, PGF-2 alpha was higher than in control cows (P less than 0.05), beginning on Day 3 of treatment and peaking on Day 5. It is concluded that the post-partum uterus increases secretion of PGF-2 alpha very early after first exposure to endogenous or exogenous progestagen.

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Section: Discussionmentioning

confidence: 99%

Effects of progestagen treatment on concentrations of prostaglandins and oxytocin in plasma from the posterior vena cava of post-partum beef cows

Cooper¹,

Carver²,

Villeneuve³

et al. 1991

Reproduction

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“…Oxytocin is thought to participate along with PGF, in a positive feedback loop that propagates the signal for luteolysis [34,35]. Although release of oxytocin-induced PGF 2 a has not been associated with initiation of functional regression, whether or not oxytocin initiates internucleosomal fragmentation has not been reported.…”

Section: Discussionmentioning

confidence: 99%

Internucleosomal DNA Fragmentation in Ovine Luteal Tissue Associated with Luteolysis: In Vivo and in Vitro Analyses1

Rueda

Wegner

Marion

et al. 1995

Biology of Reproduction

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Internucleosomal DNA fragmentation, a characteristic of apoptosis, can be visualized with agarose gel electrophoresis as discrete low-molecular-weight DNA fragments (laddering), in multiples of approximately 185 bp. CL were collected from superovulated ewes (control) or at 12 h after injection of prostaglandin F2 alpha (PGF2 alpha) on various days after hCG injection. The ability of PGF2 alpha on Days 8, 10, 12, and 14 (n > or = 3 per day per treatment) to induce luteal cell DNA fragmentation was evaluated. DNA was isolated and visualized on agarose gels. No DNA fragmentation was observed in CL from control ewes on Days 8, 10, or 12. Internucleosomal fragmentation of DNA (indicative of apoptosis) as well as nonspecific DNA fragmentation (indicative of non-apoptotic cell death) in CL from Day 14 controls was observed in two of four animals. Additionally, this pattern of DNA fragmentation was observed in CL from ewes treated with PGF2 alpha on all days. Evidence of DNA fragmentation was observed in luteal tissue after dissociation, yet no fragmentation was observed in unsliced, non-dissociated CL collected from Day 10 control ewes (incubated 4 h), or in sliced, non-incubated CL. Slicing and incubation alone were sufficient to initiate DNA fragmentation. A variety of approaches were utilized to inhibit DNA fragmentation. Only the addition of zinc acetate (1 mM) in the incubation medium throughout the 4-h incubation period prevented DNA fragmentation that was initiated by slicing (p < 0.05). There appear therefore, to be one or more intraluteal factors that directly initiate DNA fragmentation associated with cell death in luteolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…According to Kehl and Carlson (1981), l3, 14-dihydro-PGF2α caused premature luteal regression in rabbits. Watkins and Moore (1987) suggested that PG metabolites (PGMs) cause the release of oxytocin from the CL and lead to continuation of luteolytic activity. In the same context, PGF2α…”

Section: Serum Sexual Hormones Concentrationmentioning

confidence: 99%

Polyunsaturated Fatty Acids Combined with Equine Chorionic Gonadotropin to Enhance Reproductive Performance in Aged Rabbit Does

Elkomy

El-Speiy²

2015

Italian Journal of Animal Science

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Effect of systemic intravenous infusion of PGF-2 and 13,14-dihydro-15-keto-PGF-2 on the release of oxytocin-associated neurophysin from the ovary in the ewe

Cited by 16 publications

References 25 publications

Effects of progestagen treatment on concentrations of prostaglandins and oxytocin in plasma from the posterior vena cava of post-partum beef cows

Effects of progestagen treatment on concentrations of prostaglandins and oxytocin in plasma from the posterior vena cava of post-partum beef cows

Internucleosomal DNA Fragmentation in Ovine Luteal Tissue Associated with Luteolysis: In Vivo and in Vitro Analyses1

Polyunsaturated Fatty Acids Combined with Equine Chorionic Gonadotropin to Enhance Reproductive Performance in Aged Rabbit Does

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