Intrapulse changes in progesterone and LH concentrations and luteal blood flow during an estradiol-induced pulse of a metabolite of prostaglandin F2α in heifers

Imam, Shahnawaz; Shrestha, Hemanta; Beg, M.A.; Ginther, O.J.

doi:10.1016/j.anireprosci.2010.05.009

Cited by 17 publications

(8 citation statements)

References 18 publications

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“…These temporal PGFM/progesterone relationships during a simulated pulse are similar to the progesterone rebound during a spontaneous PGFM pulse late in the preluteolytic period [12,13]. The temporal association between the progesterone rebound and increase in LH in the present study confirmed our earlier report [8] and is in agreement with the results for a spontaneous [12,19] or an estradiol-induced [45] PGFM pulse.…”

Section: Discussionsupporting

confidence: 92%

“…In turn, the increase in LH may have stimulated progesterone production from SLCs, causing the progesterone rebound. This is consistent with the temporal association between an LH increase and the progesterone rebound after the peak of a spontaneous [12,19] and estradiol-induced [14,45] PGFM pulse. To our knowledge, this is the first experimental demonstration that the completion of a progesterone rebound requires an increase in LH.…”

Section: Discussionsupporting

confidence: 88%

“…A complete progesterone rebound occurred in association with the improved simulated PGFM pulse in the PGF group and is consistent with results from a simulated PGFM pulse with constant PGF infusion [8,9], a spontaneous pulse during the late preluteolytic period [12,13], and an estradiol-induced pulse on Day 14 after ovulation [34,45]. In addition, the beginning of a progesterone rebound coincided with the decrease in PGF-infusion rate and the associated decrease in PGFM concentration during the descending portion of the simulated pulse.…”

Section: Discussionsupporting

confidence: 85%

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Role of Luteinizing Hormone in Changes in Concentrations of Progesterone and Luteal Blood Flow During the Hours of a Simulated Pulse of 13,14-Dihydro-15-Keto-Prostaglandin F2alpha (PGFM) in Heifers

Shrestha¹,

Pugliesi

Beg

et al. 2011

Biology of Reproduction

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A bolus treatment (e.g., 25 mg) of prostaglandin F(2alpha) (PGF) in the study of luteolysis in cattle results in dubious interpretations. Therefore, in experiment 1 of the present study, a 13,14-dihydro-15-keto-PGF (PGFM) pulse was simulated by incremental intrauterine (IU) infusion of PGF for 2.7 h on Day 14 postovulation. Concentrations of PGFM during the first hour of infusion and at the maximum were not different between simulated (n = 7) and spontaneous (n = 7) pulses. In experiment 2, four groups (n = 6 per group) were treated at Minute 0 (beginning of infusion) as follows: saline (infused IU), PGF (infused IU), acyline/saline, and acyline/PGF. Two hours before Minute 0, each heifer was given flunixin meglumine to inhibit endogenous PGF secretion, and heifers in the acyline/saline and acyline/PGF groups were given acyline to inhibit luteinizing hormone (LH). Plasma progesterone concentrations were similar among groups during Minutes 0 to 60, with no indication of an initial transient progesterone increase in the two PGF groups. Progesterone began to decrease in the PGF groups at Minute 60 and to rebound at Minute 135 after the PGFM peak at Minute 120. The rebound was complete in association with an increase in LH in the PGF group, but it was not complete when LH was inhibited in the acyline/PGF group. Luteal blood flow increased during PGF infusion in the two PGF groups and remained elevated for approximately 2 h after the PGFM peak in the PGF group but not in the acyline/PGF group. Novel findings were that an initial transient increase in progesterone did not occur with the simulated PGFM pulse and that LH stimulated a progesterone rebound and maintained the elevated luteal blood flow after the PGFM peak.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 85%

See 1 more Smart Citation

Role of Luteinizing Hormone in Changes in Concentrations of Progesterone and Luteal Blood Flow During the Hours of a Simulated Pulse of 13,14-Dihydro-15-Keto-Prostaglandin F2alpha (PGFM) in Heifers

Shrestha¹,

Pugliesi

Beg

et al. 2011

Biology of Reproduction

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“…An increase in luteal blood flow during the hours of an expected or demonstrated progesterone rebound in cattle has been reported for spontaneous [15], induced [47], and simulated PGFM pulses [25,42]. In the initial study using the first spontaneous PGFM pulse during luteolysis, luteal blood flow increased during the ascending portion of the PGFM pulse, remained elevated for 2 h after the PGFM peak, and began to decrease when PGFM reached a low concentration (Fig.…”

Section: Role Of Luteal Blood Flow In the Progesterone Rebound In Cattlementioning

confidence: 58%

“…5). Complete rebound also occurs 14 days after ovulation when a PGFM pulse is simulated by intrauterine PGF infusion [25,42,43] or is induced by treatment with estradiol [47]. Day 14 after ovulation is well before the expected beginning of luteolysis in cattle.…”

Section: Progesterone Rebound Within a Natural Pgfm Pulse In Cattle Bmentioning

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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Circulating hormone concentrations within a pulse of a metabolite of prostaglandin F2α during preluteolysis and early luteolysis in heifers

Ginther¹,

Shrestha²,

Beg³

2010

Animal Reproduction Science

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Intrapulse changes in progesterone and LH concentrations and luteal blood flow during an estradiol-induced pulse of a metabolite of prostaglandin F2α in heifers

Cited by 17 publications

References 18 publications

Role of Luteinizing Hormone in Changes in Concentrations of Progesterone and Luteal Blood Flow During the Hours of a Simulated Pulse of 13,14-Dihydro-15-Keto-Prostaglandin F2alpha (PGFM) in Heifers

Role of Luteinizing Hormone in Changes in Concentrations of Progesterone and Luteal Blood Flow During the Hours of a Simulated Pulse of 13,14-Dihydro-15-Keto-Prostaglandin F2alpha (PGFM) in Heifers

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

Circulating hormone concentrations within a pulse of a metabolite of prostaglandin F2α during preluteolysis and early luteolysis in heifers

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