Relationships of changes in B-mode echotexture and colour-Doppler signals in the wall of the preovulatory follicle to changes in systemic oestradiol concentrations and the effects of human chorionic gonadotrophin in mares.
Abstract: A duplex grey-scale and colour-Doppler ultrasound instrument was used to study the changes in the wall of the preovulatory follicle in mares. When the follicle reached > or =35 mm (hour 0), mares were randomized into control (n = 16) and human chorionic gonadotropin (hCG)-treated (n = 16) groups. The hCG treatment was given at hour 0. Scanning was done every 12 h until hour 36, every hour between hours 36 and 48, and every 12 h thereafter until ovulation. Blood was sampled every 12 h for oestradiol assay. During the period 0-24 h post-treatment, oestradiol concentrations decreased in the hCG group and increased in the controls (significant interaction). During the period 0-36 h post-treatment, thickness and echogenicity of the granulosa increased in the hCG group but not in the controls. During the period 36 to 12 h before ovulation, granulosa and colour-Doppler end-points increased in the control and hCG groups (hour effects), while oestradiol was decreasing in both groups. The prominence and percentage of follicle circumference with an anechoic band peripheral to the granulosa and colour-Doppler signals in the follicle wall, indicating arterial blood flow, decreased during the period 4 to 1 h before ovulation (hour effects). Results indicated that the ultrasonographic changes of the wall of the preovulatory follicle were not associated temporally with changes in oestradiol concentrations and prominence of an anechoic band, and colour-Doppler signals decreased during the few hours before ovulation. The hypothesis that the latter portion of the ovulatory LH surge has a negative effect on systemic oestradiol was supported by the immediate decrease in oestradiol concentrations when hCG was injected.
Publication Date: 2006-04-06 PubMed ID: 16595721DOI: 10.1530/rep.1.01011Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study investigates the effects of human chorionic gonadotropin (hCG) on changes in the wall of the preovulatory follicle in mares, and its relationship with systemic estradiol concentrations. The results suggest that ultrasonographic changes in the follicle’s wall are not temporally correlated with estradiol changes, and that the latter part of an ovulatory LH surge has a negative effect on systemic estradiol.
Study Design and Procedures
- The study utilized a duplex grey-scale and colour-Doppler ultrasound to observe changes in the wall of the preovulatory follicle in mares.
- When the follicle reached a diameter of 35mm or larger (marked as hour 0), mares were divided into control and hCG-treated groups. Each group comprised 16 mares.
- The hCG treatment was administered at hour 0. The researchers scanned the mares every 12 hours until hour 36, every hour from hours 36 to 48, and every 12 hours subsequently until ovulation.
- Blood samples were taken every 12 hours for estradiol assay, a test to measure estradiol hormone levels in the blood.
Observations and Findings
- During the 0-24 hour period after hCG administration, estradiol concentrations decreased in the hCG group while increasing in the control group.
- From 0-36 hours following treatment, the thickness and echogenicity of the granulosa (a layer of the ovarian follicle) increased in the hCG group but remained unaltered in the control group.
- Between 36 and 12 hours before ovulation, granulosa and colour-Doppler endpoints increased in both groups, while estradiol levels decreased.
- The prominence and the percentage of the follicle’s circumference with an anechoic band (indicative of fluid content) decreased, along with a reduction in the colour-Doppler signals representing arterial blood flow in the follicle wall, during the last 4 to 1 hours before ovulation.
Conclusions
- The observed ultrasonographic changes in the follicle’s wall did not coincide temporally with fluctuations in estradiol concentrations.
- Just before ovulation, there was a decrease in the prominence of an anechoic band and colour-Doppler signals.
- The study’s results support the hypothesis that the later phase of the ovulatory LH surge has an inhibitory effect on systemic estradiol, demonstrated by the immediate fall in estradiol levels following hCG injection.
Cite This Article
APA
Gastal EL, Gastal MO, Ginther OJ.
(2006).
Relationships of changes in B-mode echotexture and colour-Doppler signals in the wall of the preovulatory follicle to changes in systemic oestradiol concentrations and the effects of human chorionic gonadotrophin in mares.
Reproduction, 131(4), 699-709.
https://doi.org/10.1530/rep.1.01011 Publication
Researcher Affiliations
- Eutheria Foundation, Cross Plains, Wisconsin 53528, USA.
MeSH Terms
- Animals
- Arteries
- Chorionic Gonadotropin / pharmacology
- Estradiol / blood
- Female
- Granulosa Cells / diagnostic imaging
- Granulosa Cells / metabolism
- Horses / physiology
- Ovarian Follicle / blood supply
- Ovarian Follicle / diagnostic imaging
- Ovarian Follicle / metabolism
- Ovulation
- Random Allocation
- Regional Blood Flow
- Stimulation, Chemical
- Time Factors
- Ultrasonography, Doppler, Color
- Ultrasonography, Doppler, Duplex
Citations
This article has been cited 7 times.- Grabowska A, Kozdrowski R. Relationship between estrus endometrial edema and progesterone production in pregnant mares two weeks after ovulation. BMC Vet Res 2022 Nov 21;18(1):414.
- Ortega-Ferrusola C, Gómez-Arrones V, Martín-Cano FE, Gil MC, Peña FJ, Gaitskell-Phillips G, Da Silva-Álvarez E. Advances in the ultrasound diagnosis in equine reproductive medicine: New approaches. Reprod Domest Anim 2022 Oct;57 Suppl 5(Suppl 5):34-44.
- Bottrel M, Ortiz I, Hidalgo M, Díaz-Jiménez M, Pereira B, Consuegra C, Yousef MS, Dorado J. Hormonal Management for the Induction of Luteolysis and Ovulation in Andalusian Jennies: Effect on Reproductive Performance, Embryo Quality and Recovery Rate. Animals (Basel) 2022 Jan 8;12(2).
- Ribeiro MO, Bittencourt RF, Feliciano MAR, Santana ALA, Silva MAA, Felix MD, Santana LR, Barbosa LP. Subdose of human chorionic gonadotropin applied at the Hou Hai acupoint on follicular dynamics and luteal development in donkeys. Anim Reprod 2020 Nov 25;17(4):e20200554.
- Derar RI, Hussein HA. Ovarian Follicular Dynamics during the Estrous Cycle in Jennies in Upper Egypt. Vet Med Int 2011;2011:860518.
- Alkhadrawy JMH, Aboelmaaty AM, Abou-Ahmed MM, Ghallab AM. Effect of hCG and prostaglandin on ovarian, luteal development, and hormonal changes in embryo donor mares during the hot summer months in subtropics. Open Vet J 2024 Aug;14(8):2057-2072.
- Alkhadrawy JMH, Aboelmaaty AM, Abou-Ahmed MM, Ghallab AM. Effect of breeding season and age on follicular dynamics and hemodynamics in embryo donor mares subjected to luteolysis after embryo flushing. Open Vet J 2024 Mar;14(3):852-865.
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