Hormone concentration changes temporally associated with the hour of transition from preluteolysis to luteolysis in mares

Ginther, O.J.; Beg, M.A.

doi:10.1016/j.anireprosci.2011.09.013

Cited by 20 publications

(15 citation statements)

References 32 publications

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“…The luteal transition between preluteolysis and luteolysis in mares is manifested within 1 h, based on hourly determination of P4 concentration and occurred between 2 PM and 2 AM in eight of eight mares [31]. In the current study, eight of nine mares that were in preluteolysis at the beginning of hourly sampling at 2 PM began the transition between preluteolysis and luteolysis at 5, 6, or 7 PM.…”

Section: Discussionmentioning

confidence: 50%

“…In addition, samples were collected hourly for 12 h on Day 14 (beginning at 2 PM). Beginning sampling at 2 PM was based on a report that eight of eight mares began luteolysis between 2 PM and 2 AM [31]. Hourly sampling extended from 3 h before to 8 h after the fifth sulpiride treatment at 8-h intervals.…”

Section: Experimental Design and Treatmentsmentioning

confidence: 99%

“…The luteal transition from preluteolysis to luteolysis was based on a progressive decrease in P4 at the peaks of P4 fluctuations, as described [31]. The period before luteal transition was defined as preluteolysis.…”

Section: Experimental Design and Treatmentsmentioning

confidence: 99%

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Ovarian and PGF2α responses to stimulation of endogenous PRL pulses during the estrous cycle in mares

Pinaffi¹,

Khan²,

Silva

et al. 2012

Theriogenology

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Section: Discussionmentioning

confidence: 50%

Section: Experimental Design and Treatmentsmentioning

confidence: 99%

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Ovarian and PGF2α responses to stimulation of endogenous PRL pulses during the estrous cycle in mares

Pinaffi¹,

Khan²,

Silva

et al. 2012

Theriogenology

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“…Luteal transition between preluteolysis and luteolysis occurs within 1 h as manifested by changes in progesterone concentration, based on blood sampling every hour in both cattle [46] and horses [56] (Figs. 5 and 6).…”

Section: The Transitional Progesterone Rebound In Cattlementioning

confidence: 99%

Dynamics of Circulating Progesterone Concentrations Before and During Luteolysis: A Comparison Between Cattle and Horses1

Ginther

Beg

2012

Biology of Reproduction

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The profile of circulating progesterone concentration is more dynamic in cattle than in horses. Greater prominence of progesterone fluctuations in cattle than in horses reflect periodic interplay in cattle between pulses of a luteotropin (luteinizing hormone; LH) and pulses of a luteolysin (prostaglandin F2alpha; PGF2alpha). A dose of PGF2alpha that induces complete regression of a mature corpus luteum with a single treatment in cattle or horses is an overdose. The overdose effects on the progesterone profile in cattle are an immediate nonphysiological increase taking place over about 30 min, a decrease to below the original concentration, a dose-dependent rebound 2 h after treatment, and a progressive decrease until the end of luteolysis. An overdose of PGF2alpha in horses results in a similar nonphysiological increase in progesterone followed by complete luteolysis; a rebound does not occur. An overdose of PGF2alpha and apparent lack of awareness of the rebound phenomenon has led to faulty interpretations on the nature of spontaneous luteolysis. A transient progesterone suppression and a transient rebound occur within the hours of a natural PGF2alpha pulse in cattle but not in horses. Progesterone rebounds are from the combined effects of an LH pulse and the descending portion of a PGF2alpha pulse. A complete transitional progesterone rebound occurs at the end of preluteolysis and the beginning of luteolysis and returns progesterone to its original concentration. It is proposed that luteolysis does not begin in cattle until after the transitional rebound. During luteolysis, rebounds are incomplete and gradually wane. A partial rebound during luteolysis in cattle is associated with a concomitant increase in luteal blood flow. A similar increase in luteal blood flow does not occur in mares.

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“…Each PGFM pulse that occurs during luteolysis is temporally associated with a pulse of oxytocin (OT) [9]. The small transitional pulse at the hour of the initiation of luteolysis is also associated with a pulse of OT, whereas previous small PGFM pulses are not [10]. Oxytocin therefore may play a role in the effectiveness of a PGF2a pulse during luteolysis and the effectiveness of the small transitional pulse at the initiation of luteolysis in mares (review [2]).…”

Section: Introductionmentioning

confidence: 98%

Oxytocin induction of pulses of a prostaglandin metabolite and luteolysis in mares

et al. 2015

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Hormone concentration changes temporally associated with the hour of transition from preluteolysis to luteolysis in mares

Cited by 20 publications

References 32 publications

Ovarian and PGF2α responses to stimulation of endogenous PRL pulses during the estrous cycle in mares

Ovarian and PGF2α responses to stimulation of endogenous PRL pulses during the estrous cycle in mares

Dynamics of Circulating Progesterone Concentrations Before and During Luteolysis: A Comparison Between Cattle and Horses1

Oxytocin induction of pulses of a prostaglandin metabolite and luteolysis in mares

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