Disruption of the periovulatory LH surge by a transient increase in circulating 17 beta-estradiol at the time of ovulation in mares

作者：Ginther O J^*; Almamun M; Shahiduzzaman A K M; Beg M A

来源：Animal Reproduction Science, 2010, 117(1-2): 178-182.

DOI：10.1016/j.anireprosci.2009.04.003

• Estradiol
• FSH
• LH
• Mares
• Ovulation

The mechanism for a reported temporal association between ovulation and a transient disruption in the periovulatory increase in LH concentrations was studied in nine mares treated with human chorionic gonadotropin when the preovulatory follicle was >= 32 mm. Examinations for ovulation detection and blood collection were done at 2-h intervals and the results were retrospectively centralized to ovulation (Hour 0). Concentrations of LH began to increase (P < 0.03) rapidly at Hour -18, decreased (P < 0.04) between Hours 0 and 6, and again increased (P < 0.0001) after Hour 12. A progressive decrease (P < 0.0001) in estradiol between Hours -30 and 24 was interrupted temporarily by an increase (P < 0.01) between Hours -2 and 0 and a decrease (P < 0.007) between Hours 0 and 2. Results indicated that a disruption and depression in the periovulatory LH surge occurred at the time of detected ovulation in mares and was temporally associated with a transient increase in estradiol during an overall progressive decline. The disruption in LH concentrations is attributable to the estradiol increase, based on a reported negative effect of estradiol on LH. The source of the circulating estradiol was likely from the discharge of estradiol-laden follicular fluid into the abdomen during ovulation and rapid absorption of estradiol into the circulation.

• 出版日期2010-1