Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma
<p>Abstract</p> <p>Background</p> <p>The purpose of the study was to determine if the effect of llama OIF on LH secretion is mediated by stimulation of the hypothalamus or pituitary gland.</p> <p>Methods</p> <p>Using a 2-by-2 factorial design to...
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| Format: | Article |
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BMC
2011-05-01
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| Series: | Reproductive Biology and Endocrinology |
| Online Access: | http://www.rbej.com/content/9/1/74 |
| _version_ | 1828221227591794688 |
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| author | Letelier Claudia Valderrama Ximena P Guerra Monserrat Smulders Juan P Silva Mauricio E Adams Gregg P Ratto Marcelo H |
| author_facet | Letelier Claudia Valderrama Ximena P Guerra Monserrat Smulders Juan P Silva Mauricio E Adams Gregg P Ratto Marcelo H |
| author_sort | Letelier Claudia |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>The purpose of the study was to determine if the effect of llama OIF on LH secretion is mediated by stimulation of the hypothalamus or pituitary gland.</p> <p>Methods</p> <p>Using a 2-by-2 factorial design to examine the effects of OIF vs GnRH with or without a GnRH antagonist, llamas with a growing ovarian follicle greater than or equal to 8 mm were assigned randomly to four groups (n = 7 per group) and <b>a) </b>pre-treated with 1.5 mg of GnRH antagonist (cetrorelix acetate) followed by 1 mg of purified llama OIF, <b>b) </b>pre-treated with 1.5 mg of cetrorelix followed by 50 micrograms of GnRH, <b>c) </b>pre-treated with a placebo (2 ml of saline) followed by 1 mg of purified llama OIF or <b>d) </b>pre-treated with a placebo (2 ml of saline) followed by 50 micrograms of GnRH. Pre-treatment with cetrorelix or saline was given as a single slow intravenous dose 2 hours before intramuscular administration of either GnRH or OIF. Blood samples for LH measurement were taken every 15 minutes from 1.5 hours before to 8 hours after treatment. The ovaries were examined by ultrasonography to detect ovulation and CL formation. Blood samples for progesterone measurement were taken every-other-day from Day 0 (day of treatment) to Day 16.</p> <p>Results</p> <p>Ovulation rate was not different (P = 0.89) between placebo+GnRH (86%) and placebo+OIF groups (100%); however, no ovulations were detected in llamas pre-treated with cetrorelix. Plasma LH concentrations surged (P < 0.01) after treatment in both placebo+OIF and placebo+GnRH groups, but not in the cetrorelix groups. Maximum plasma LH concentrations and CL diameter profiles did not differ between the placebo-treated groups, but plasma progesterone concentrations were higher (P < 0.05), on days 6, 8 and 12 after treatment, in the OIF- vs GnRH-treated group.</p> <p>Conclusion</p> <p>Cetrorelix (GnRH antagonist) inhibited the preovulatory LH surge induced by OIF in llamas suggesting that LH secretion is modulated by a direct or indirect effect of OIF on GnRH neurons in the hypothalamus.</p> |
| first_indexed | 2024-04-12T16:38:16Z |
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| language | English |
| last_indexed | 2024-04-12T16:38:16Z |
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| spelling | doaj.art-015abae672484b3c86075c502fb007502022-12-22T03:24:54ZengBMCReproductive Biology and Endocrinology1477-78272011-05-01917410.1186/1477-7827-9-74Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasmaLetelier ClaudiaValderrama Ximena PGuerra MonserratSmulders Juan PSilva Mauricio EAdams Gregg PRatto Marcelo H<p>Abstract</p> <p>Background</p> <p>The purpose of the study was to determine if the effect of llama OIF on LH secretion is mediated by stimulation of the hypothalamus or pituitary gland.</p> <p>Methods</p> <p>Using a 2-by-2 factorial design to examine the effects of OIF vs GnRH with or without a GnRH antagonist, llamas with a growing ovarian follicle greater than or equal to 8 mm were assigned randomly to four groups (n = 7 per group) and <b>a) </b>pre-treated with 1.5 mg of GnRH antagonist (cetrorelix acetate) followed by 1 mg of purified llama OIF, <b>b) </b>pre-treated with 1.5 mg of cetrorelix followed by 50 micrograms of GnRH, <b>c) </b>pre-treated with a placebo (2 ml of saline) followed by 1 mg of purified llama OIF or <b>d) </b>pre-treated with a placebo (2 ml of saline) followed by 50 micrograms of GnRH. Pre-treatment with cetrorelix or saline was given as a single slow intravenous dose 2 hours before intramuscular administration of either GnRH or OIF. Blood samples for LH measurement were taken every 15 minutes from 1.5 hours before to 8 hours after treatment. The ovaries were examined by ultrasonography to detect ovulation and CL formation. Blood samples for progesterone measurement were taken every-other-day from Day 0 (day of treatment) to Day 16.</p> <p>Results</p> <p>Ovulation rate was not different (P = 0.89) between placebo+GnRH (86%) and placebo+OIF groups (100%); however, no ovulations were detected in llamas pre-treated with cetrorelix. Plasma LH concentrations surged (P < 0.01) after treatment in both placebo+OIF and placebo+GnRH groups, but not in the cetrorelix groups. Maximum plasma LH concentrations and CL diameter profiles did not differ between the placebo-treated groups, but plasma progesterone concentrations were higher (P < 0.05), on days 6, 8 and 12 after treatment, in the OIF- vs GnRH-treated group.</p> <p>Conclusion</p> <p>Cetrorelix (GnRH antagonist) inhibited the preovulatory LH surge induced by OIF in llamas suggesting that LH secretion is modulated by a direct or indirect effect of OIF on GnRH neurons in the hypothalamus.</p>http://www.rbej.com/content/9/1/74 |
| spellingShingle | Letelier Claudia Valderrama Ximena P Guerra Monserrat Smulders Juan P Silva Mauricio E Adams Gregg P Ratto Marcelo H Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma Reproductive Biology and Endocrinology |
| title | Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma |
| title_full | Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma |
| title_fullStr | Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma |
| title_full_unstemmed | Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma |
| title_short | Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma |
| title_sort | cetrorelix suppresses the preovulatory lh surge and ovulation induced by ovulation inducing factor oif present in llama seminal plasma |
| url | http://www.rbej.com/content/9/1/74 |
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