Lack of LH Response to Exogenous Estradiol in Heifers with ACTH-Induced Ovarian Follicular Cysts.

Ribadu, Abdullahi Y.; Nakada, Ken; Tanaka, Yoshinobu; Moriyoshi, Masaharu; Zhang, Wen Chang; Nakao, Toshihiko

doi:10.1292/jvms.61.979

Cited by 12 publications

(8 citation statements)

References 20 publications

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“…8). Our results [11,12,22] and those of many other studies [7,8,[13][14][15][16][17][18] suggest that the key physiological change in cystic cows is an abnormality in LH secretion. Under normal conditions, a sufficient amount of estradiol induces an LH surge and the dominant follicle ovulates.…”

Section: Model For Mechanism Of Development Of Follicular Cystssupporting

confidence: 82%

“…Exogenous injection of estradiol often fails to induce an LH surge in cows with naturally occurring or induced follicular cysts [14][15][16][17][18], whereas injection of GnRH can induce the release of LH [19][20][21]. Taken together, these findings strongly suggest that an important physiological change in cystic cows is the lack of an LH surge owing to a functional abnormality in the estradiolfeedback regulation of LH secretion.…”

Section: Induction Of Follicular Cyst Formation By Perturbation Of Esmentioning

confidence: 95%

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Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release

Todoroki

Kaneko

2006

Journal of Reproduction and Development

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Abstract. Follicular cysts in cattle result from excessive growth of the dominant follicle without ovulation and still constitute a major reproductive disorder in this species. One key hormonal characteristic of cows with follicular cysts is the lack of an LH surge, although they have increased plasma estradiol concentrations. Another is a relatively high level of pulsatile secretion of LH that promotes continued growth of the dominant follicle. These LH characteristics seem to result from a functional abnormality in the feedback regulation of LH secretion by estradiol. Treatment with controlled internal drug release devices that increase circulating progesterone levels is effective in resolving follicular cystic conditions by 1) lowering pulsatile LH secretion and 2) restoring the ability of the hypothalamo-pituitary axis to generate an LH surge in response to an increase in circulating estradiol.

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Section: Model For Mechanism Of Development Of Follicular Cystssupporting

confidence: 82%

Section: Induction Of Follicular Cyst Formation By Perturbation Of Esmentioning

confidence: 95%

Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release

Todoroki

Kaneko

2006

Journal of Reproduction and Development

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“…About 50% of cows became anovular following these treatments (Cook et al 1990, Hamilton et al 1995, Calder et al 1999. Cows with induced follicular cysts appear to be in a physiological state in which high circulating E 2 either produces a delayed GnRH/LH surge (Zaied et al 1981) or does not cause a GnRH/LH surge (Dobson & Alam 1987, Refsal et al 1987, Ribadu et al 1999 due to altered hypothalamic responsiveness to E 2 . However, this is the first study, to our knowledge, that has shown that this lack of hypothalamic responsiveness to E 2 and follicular cysts can be induced by the normal increase in E 2 simply by preventing the post-ovulatory rise in circulating P 4 .…”

Section: Discussionmentioning

confidence: 99%

Follicular cysts occur after a normal estradiol-induced GnRH/LH surge if the corpus hemorrhagicum is removed

Gümen

Wiltbank²

2005

Reproduction

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The pathophysiology underlying follicular cysts appears to be lack of an estradiol (E 2 )-induced GnRH/LH surge due to hypothalamic insensitivity to E 2 . In addition, progesterone (P 4 ) can cause animals with follicular cysts to resume normal cyclicity and normal hypothalamic responsiveness to E 2 . We postulated that follicular cysts may be a pathological manifestation of a physiological state that cows, and possibly other species, go through during the normal estrous cycle but the rise in P 4 following ovulation induces them back to normal hypothalamic responsiveness to E 2 . Based on this hypothesis, we expected that removal of the ovary containing the corpus hemorrhagicum would prevent the normal rise in P 4 following ovulation and induce development of follicular cysts. Cows (n 5 24) on day 7 of the estrous cycle were treated with prostaglandin F 2a (PGF 2a ) and time of ovulation was detected by ovarian ultrasonography every 8 h. Immediately following detection of ovulation, cows were randomly but unequally assigned to have the ovary containing the corpus hemorrhagicum removed (TRT; n 5 16) or the ovary opposite to the corpus hemorrhagicum removed (CON; n 5 8). Cows were subsequently evaluated by daily ultrasound and blood sampling to determine follicular dynamics. Ovulation was detected at 93.7 6 4.5 h after PGF 2a injection. All CON cows had a normal estrous cycle length (22.0 6 0.6 days) after ovariectomy (OVX). Half of the TRT cows became anovular (TRT-ANO; n 5 8) after OVX with large anovular follicles developing on the ovary (maximal size, 25.4 6 1.4 mm; range, 20-32 mm). However, eight TRT cows ovulated (TRT-OV; n 5 8) 7.3 6 0.6 days after OVX. Control cows had a normal P 4 rise after ovulation. Removal of the newly formed corpus hemorrhagicum prevented the rise in circulating serum P 4 in TRT-ANO cows throughout the 25-day experimental period. The TRT-OV cows had a delayed increase in circulating P 4 but it was normal in relation to time of ovulation. Serum E 2 concentrations were similar among groups (TRT-OV, TRT-ANO and CON cows) until 7 days after OVX. Serum E 2 concentrations then decreased in TRT-OV and CON cows but remained elevated (> 5 pg/ml) in TRT-ANO cows. Thus, the endogenous increase in circulating E 2 that induces the GnRH/LH surge and estrus is sufficient to induce cows into a physiological state that resembles follicular cysts if it is not followed by increased circulating P 4 . Reproduction (2005) 129 737-745Introduction Follicular cysts have been reported in many mammalian species, including cattle (Roberts 1971, Kesler & Garverick 1982, swine (Heinonen et al. 1998), dogs (Arbeiter 1993, rabbits (Lopez-Bejar et al. 1998), rats (Brawer et al. 1986), mares (McCue & Squires 2002), sheep (Christman et al. 2000), elephants (Brown et al. 1999) and women (Stein & Leventhal 1935). In cattle, this condition is characterized by large (generally $25 mm in diameter) anovular structures that persist on the ovary for at least 10 days in the absence of a corpus luteum (CL) (Roberts 1...

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“…Many cattle had cystic follicular structure observed from 15-45 days after parturition, and follicular cysts as a reproductive disease were mainly diagnosed at 1 to 4 months after parturition. As for the cause of follicular cysts, it was considered that the hypothalamus and pituitary gland were not able to respond to high concentrations of blood estradiol-17β (E 2 ) for induction of estrous events including preovulatory GnRH-LH surge secretion [16,22]. It was thought that a factors in the induction of these reproductive disorders are to feed a large amount of concentrate for milk production and/or much stress applied to the body by milking, housing and feeding systems in high yield dairy cattle [4,8,22].…”

mentioning

confidence: 99%

Changes in Interleukin-6 Concentration in Peripheral Blood of Pre- and Post-Partum Dairy Cattle and Its Relationship to Postpartum Reproductive Diseases

et al. 2004

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ABSTRACT. Reproductive diseases after parturition are a serious problem in dairy cattle. It is important to predict postpartum reproducti ve diseases early and to develop prophylaxis. The objectives of this study were to demonstrate changes in the peripheral blood con centration of interleukin-6 (IL-6) before parturition, which was mainly produced by T helper 2 type (Th2) cells, and to investigate a correlation between the IL-6 concentration and the occurrence of the postpartum retained placenta, endometritis and/or follicular cyst in da iry cattle. Twenty-seven Holstein-Friesian cows were used for this study. Thirteen had no clinical disease, 8 had retained placenta, 4 were diagnosed with endometritis by vaginal inspection, and 2 were diagnosed with follicular cyst by rectal palpation at 1 and 2 months a fter parturition. Blood samples were collected 60 days pre-and post-partum. They used for IL-6, progesterone (P 4 ) and estradiol-17β (E 2 ) concentration determination. This study showed that the IL-6 concentration prepartum was higher than postpartum. Low levels of IL-6 and P 4 in peripheral blood prepartum tended to affect retained placenta and a high level of IL-6 prepartum tended to affect endometrit is. These results indicate that measurement of change in the IL-6 concentration during pregnancy is one useful tool for predicting crisis in postpartum reproductive diseases in dairy cattle. KEY WORDS: cattle, endometritis, interleukin-6, pregnant, retained placenta.

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Lack of LH Response to Exogenous Estradiol in Heifers with ACTH-Induced Ovarian Follicular Cysts.

Cited by 12 publications

References 20 publications

Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release

Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release

Follicular cysts occur after a normal estradiol-induced GnRH/LH surge if the corpus hemorrhagicum is removed

Changes in Interleukin-6 Concentration in Peripheral Blood of Pre- and Post-Partum Dairy Cattle and Its Relationship to Postpartum Reproductive Diseases

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