Blood LH after PGF2α in diestrous and ovariectomized cattle

Hafs, H. D.; Louis, Thomas M.; Stellflug, J. N.; Convey, E. M.; Britt, J.H.

doi:10.1016/s0090-6980(75)80047-5

Cited by 20 publications

(5 citation statements)

References 15 publications

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“…An increase in LH concentrations does not occur if PG is administered when a functional corpus luteum is not present (Hafs, Louis, Stellflug, Convey & Britt, 1975;Furr, Cooper, Jackson, Hart & Pope, 1981). Therefore, since progesterone is a potent inhibitor of LH secretion (Convey, Beck, Neitzel, Bostwick & Hafs, 1977 ; Ireland & Roche, 1982a) the increase in LH concentrations after a luteolytic injection of PG in cows is probably the result of a reduction in negative feedback due to the decreasing progesterone concentrations.…”

Section: Discussionmentioning

confidence: 99%

Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during prostaglandin-induced regression of the corpus luteum in the cow

Schallenberger¹,

Schams²,

Bullermann³

et al. 1984

Reproduction

144

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A luteolytic dose (500 micrograms) of cloprostenol was given on Day 12 of the oestrous cycle to 5 heifers. Blood samples were collected simultaneously from the caudal vena cava and jugular vein at 5-20-min intervals from -6 to 0 (control period), 0 to 12 and 24 to 36 h after PG injection. Pulses of LH were secreted concomitantly with pulses of FSH during all sampling periods. However, during the control period separate FSH pulses were detected resulting in a shorter (P less than 0.01) interpulse interval for FSH than LH (93 versus 248 min). LH and FSH pulse frequencies increased (P less than 0.01) beginning 1-3 h after PG to interpulse intervals of 59 and 63 min, respectively, and continued to be maintained 24-36 h after PG. Concomitantly there was a 2-3-fold increase (P less than 0.01) in basal concentrations and pulse amplitude for LH (but not FSH). FSH basal concentrations and pulse amplitudes decreased (P less than 0.05) in 3 heifers 24-36 h after PG. Pulsatile secretion of oestradiol was observed at frequencies similar to LH during the periods 4-12 h (3 heifers) and 24-36 h (2 heifers) after PG, respectively, resulting in higher (P less than 0.05) mean oestradiol concentrations. Progesterone concentrations in the vena cava increased (P less than 0.01) 5-10 min after PG but decreased (P less than 0.01) 67% by 20 min after PG. This decrease was followed by a rise (P less than 0.05) beginning 2-3 h after PG and lasting for an average of 3.3 h.(ABSTRACT TRUNCATED AT 400 WORDS)

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Section: Discussionmentioning

confidence: 99%

Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during prostaglandin-induced regression of the corpus luteum in the cow

Schallenberger¹,

Schams²,

Bullermann³

et al. 1984

Reproduction

144

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“…It has been shown that the ovulatory effect of PGF is not only local at the follicular level but also at the neurocrine hypothalamusÀhypophysis axis in the central nervous system in horses 1 and cattle. 6 That study showed an immediate increase of follicle-stimulating hormone (FSH) and LH in peripheral blood and a later rise of gonadotropin-releasing hormone after administration of luprostiol, a PGF analog in transitional mares, resulting in continued elevation of blood concentrations of FSH and LH for several hours. 1 Although the horse is regarded as a monovular species, 7 multiple ovulation is not uncommon.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Cloprostenol on the Incidence of Multiple Ovulation and Anovulatory Hemorrhagic Follicles in Two Mares: A Case Report

Cuervo‐Arango

Newcombe²

2009

Journal of Equine Veterinary Science

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Reproductive records of the entire lives of two mares with abnormally high incidence of multiple ovulation and hemorrhagic anovulatory follicles were analyzed retrospectively. Chi-square analysis was used to test statistically the effect of cloprostenol, a prostaglandin F2 analog, on the incidence of multiple ovulations, hemorrhagic anovulatory follicles, and its ultrasonographic appearance. A total of 319 estrous cycles during a 17-year period were analyzed. Cycles induced with cloprostenol were more likely (P < .000) to develop hemorrhagic anovulatory follicles than spontaneous cycles. The incidence of multiple ovulation was higher in induced cycles than in spontaneous cycles in one of the two mares.

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“…Although PGF is best known for its luteolytic effect, it also causes immediate release of LH 3 resulting in induction of ovulation in numerous species 4,5,6,7 including equine. 8,9,10 There is clinical and scientific evidence that administration of a PGF analogue may induce oestrus and / or ovulation even in mares with baseline plasma progesterone concentration without a preceding luteolysis.…”

Section: Introductionmentioning

confidence: 99%

Effect of Dose of Cloprostenol on the Interval to Ovulation in the Diestrous Mare: A Retrospective Study

Newcombe¹,

Jöchle

Cuervo‐Arango

2008

Journal of Equine Veterinary Science

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Although the ovulatory effects of prostaglandins are well documented in several domestic species included horses, there has been little attention paid to the use of this ovulatory effect for clinical purposes. Mares often grow large follicles during the luteal phase that may or may not ovulate before progesterone levels decline. Clinical observations of administering prostaglandins in diestrus mares with large follicles suggest that there may be a negative correlation between follicular diameter and interval from treatment to ovulation. The objectives of this study were two fold: to investigate the Cloprostenol dose rate effect on interval to ovulation and to confirm the negative correlation between follicular diameter and the interval to ovulation. The hypothesis tested was that high doses of Cloprostenol given in diestrus to mares with larger follicles would induce ovulation more rapidly than in mares given lower doses and or with smaller follicles. In order to test the hypothesis, a total of 1234 estrous cycles were induced with different doses of Cloprostenol (ranged from 8.75 to 625 µg). All mares had at least a follicle ≥ 28 mm. Dominant follicles were followed by transrectal ultrasound examinations every other day until ovulation was detected. There was a significant effect of dose (P = 0.000) and follicular diameter (P = 0.000) on the interval from treatment to ovulation. The shortest mean interval (2.4 days) was observed after administration of 625 µg in mares with follicles ≥ 36 mm whereas the longest (4.9 days) after 8.75 µg in follicles of 28-31 mm.

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Blood LH after PGF2α in diestrous and ovariectomized cattle

Cited by 20 publications

References 15 publications

Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during prostaglandin-induced regression of the corpus luteum in the cow

Pulsatile secretion of gonadotrophins, ovarian steroids and ovarian oxytocin during prostaglandin-induced regression of the corpus luteum in the cow

The Effect of Cloprostenol on the Incidence of Multiple Ovulation and Anovulatory Hemorrhagic Follicles in Two Mares: A Case Report

Effect of Dose of Cloprostenol on the Interval to Ovulation in the Diestrous Mare: A Retrospective Study

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