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Cortisol delays the estradiol-induced LH surge : is this dependent on prior ovarian steroid exposure?

Wagenmaker, Elizabeth, Breen, Kellie, Clarke, Iain, Oakley, Amy, Tilbrook, Alan, Turner, Anne and Karsch, Fred 2005, Cortisol delays the estradiol-induced LH surge : is this dependent on prior ovarian steroid exposure?, Biology of reproduction, vol. 72, no. Supplement 1.

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Title Cortisol delays the estradiol-induced LH surge : is this dependent on prior ovarian steroid exposure?
Author(s) Wagenmaker, Elizabeth
Breen, Kellie
Clarke, Iain
Oakley, Amy
Tilbrook, Alan
Turner, AnneORCID iD for Turner, Anne orcid.org/0000-0002-0682-2860
Karsch, Fred
Journal name Biology of reproduction
Volume number 72
Issue number Supplement 1
Total pages 1 journal article
Publisher Society for the Study of Reproduction
Place of publication Champaign, Ill.
Publication date 2005
ISSN 0006-3363
0523-6754
1529-7268
Keyword(s) cortisol
luteinizing hormone surge
estradiol
positive feedback
Summary Glucocorticoids can inhibit pulsatile LH secretion and can delay or even block the preovulatory LH surge. Previous work in ovariectomized ewes has indicated that cortisol can delay the estradiol-induced LH surge in an artificial follicular phase model but the results suggest this effect may be influenced by prior exposure to ovarian steroids. Here we tested the hypothesis that this disruptive effect of cortisol on the positive feedback action of estradiol is dependent on prior exposure to the ovarian steroidal milieu of the estrous cycle. Using long-term ovariectomized ewes, sequential artificial estrous cycles were created in the anestrous season by treatment and subsequent withdrawal of progesterone (CIDRs inserted for 9 d) followed by estradiol implants simulating the pre-ovulatory estradiol rise that induces the LH surge. Following the first artificial estrous cycle, a second cycle was initiated. Progesterone was again administered for 9 d followed by a second artificial follicular phase two weeks later. Beginning 2 hr prior to estradiol administration and ending at 40 hr, animals received either a cortisol infusion (elevate plasma levels to ∼170 ng/ml) or vehicle. Jugular blood was sampled hourly to assess occurrence and timing of the LH surge. Four different treatment sequences were tested (Cycle 1-Cycle 2): cortisol-cortisol; vehicle-cortisol; cortisol-vehicle; and vehicle-vehicle (n=5-6/sequence). If prior exposure to the ovarian steroidal milieu of the estrous cycle was necessary for cortisol to interfere with the positive feedback action of estradiol, then we would predict that cortisol would only delay the LH surge when it was delivered in Cycle 2 but not Cycle 1. Our results failed to support this prediction. Cortisol delayed the surge in both cycles (p<0.01), and the extent of the delay was the same in both Cycles 1 and 2 (4 hrs). Cortisol did not significantly affect surge amplitude in either cycle. These findings reinforce our previous conclusion that cortisol can delay the estradiol-induced LH surge but they do not support the hypothesis that this action of cortisol is dependent upon exposure to the ovarian steroidal milieu of the previous estrous cycle. (NIH-HD-30773)
Language eng
Field of Research 111404 Reproduction
HERDC Research category C1.1 Refereed article in a scholarly journal
Persistent URL http://hdl.handle.net/10536/DRO/DU:30022133

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