Inhibition of intrafollicular PGE2 synthesis and ovulation following ultrasound-mediated intrafollicular injection of the selective cyclooxygenase-2 inhibitor NS-398 in cattle1
| Autor: | George W. Smith, J.R. Pursley, M. W. Peters |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
endocrine system
medicine.medical_specialty medicine.drug_class Chemistry media_common.quotation_subject General Medicine Luteal phase Follicular fluid Follicle medicine.anatomical_structure Endocrinology Internal medicine Follicular phase Genetics medicine Endocrine system Animal Science and Zoology Gonadotropin Corpus luteum Ovulation Food Science media_common |
| Zdroj: | Journal of Animal Science. 82:1656-1662 |
| ISSN: | 1525-3163 0021-8812 |
| DOI: | 10.2527/2004.8261656x |
| Popis: | Ultrasound-mediated intrafollicular injection and aspiration procedures were used to investigate the ability of the selective cyclooxygenase-2 inhibitor, NS-398, to inhibit intrafollicular PGE 2 synthesis and suppress ovulation in dairy cattle. Follicular growth and timing of the preovulatory gonadotropin surge were synchronized in 55 Holstein cows and the position of the ovulatory follicle was determined by daily ultrasound scanning. Preovulatory follicular fluid was aspirated from the largest follicle in four animals at 0, 6, 12, 18, and 24 h after GnRH injection (n = 20). The remaining 35 animals were subjected to ultrasound-mediated intrafollicular injection of NS-398 (10 μM final concentration; n = 19) or diluent (n = 16; controls). At 24 h after GnRH injection, follicular fluid was harvested from a subset of NS-398- (n = 9) and diluent-treated animals (n = 6). The remaining NS-398- and diluent-treated animals were subjected to ultrasonography every 6 h for 36 h after intrafollicular injection, and then daily through d 7 of the subsequent luteal phase to monitor ovulation and corpus luteum development. Follicular fluid PGE 2 concentrations were increased following GnRH injection and reached a maximum at 24 h (P < 0.05). Follicular fluid PGE 2 concentrations were decreased in NS-398- vs. diluent-treated follicles (7.2 vs. 52.2 ng/mL respectively; P < 0.05), but progesterone concentrations did not differ. Intrafollicular injection of NS-398 also inhibited follicle rupture (P < 0.001). All 10 control animals ovulated within 30 h of GnRH injection. Nine out of the ten NS-398-injected animals failed to ovulate. The NS-398-injected follicles developed morphological and endocrine characteristics resembling luteinized, unruptured follicles. Thus, intrafollicular PGE 2 synthesis and follicle rupture, but not luteinization, were inhibited in cattle following ultrasound-mediated intrafollicular injection of NS-398. Ultrasound-mediated intrafollicular injection of NS-398 is a useful tool for mechanistic studies of intrafollicular regulation of the ovulatory process in cattle. |
| Databáze: | OpenAIRE |
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