Frequency of luteinizing hormone pulses in cattle influences duration of persistence of dominant ovarian follicles, follicular fluid concentrations of steroids, and activity of insulin-like growth factor binding proteins
| Autor: | D.V. Mariscal-Aguayo, M. Garcia-Winder, J. E. Kinder, Andrea S. Cupp, E. G. M. Bergfeld, T. Sanchez-Torres, M. E. Wehrman, F. N. Kojima, Debra T. Clopton, K.E. Fike, Andrew J. Roberts |
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| Rok vydání: | 2003 |
| Předmět: |
Periodicity
medicine.medical_specialty Follicular Atresia Biology Follicle Follicle-stimulating hormone Endocrinology Ovarian Follicle Food Animals Internal medicine Follicular phase medicine Animals Ovarian follicle Progesterone Ultrasonography Estrous cycle Estradiol Follicular atresia General Medicine Luteinizing Hormone Follicular fluid Follicular Fluid Insulin-Like Growth Factor Binding Proteins Administration Intravaginal Insulin-Like Growth Factor Binding Protein 2 Insulin-Like Growth Factor Binding Protein 3 medicine.anatomical_structure Insulin-Like Growth Factor Binding Protein 4 Female Steroids Animal Science and Zoology Follicle Stimulating Hormone Insulin-Like Growth Factor Binding Protein 5 Luteinizing hormone |
| Zdroj: | Animal Reproduction Science. 77:187-211 |
| ISSN: | 0378-4320 |
| Popis: | The objectives of the present study were to determine how varying frequency of LH pulses as controlled by varying treatments with progesterone (P4) in cattle would affect: (1) concentration of steroid hormones and activity of insulin-like growth factor binding proteins (IGFBPs) in the ovarian follicular fluid and blood plasma, and (2) duration of persistence of largest ovarian follicles. There were four treatment groups (n=7 per group) and a control group (n=5) of mature, non-lactating beef cows. Treatments were: (1) two progesterone releasing intravaginal devices (PRIDs) for 16 days (2PRID); (2) a half PRID for 16 days (0.5PRID); (3) two PRIDs for 8 days, then a half PRID for 8 days (2-0.5PRID); or (4) a half PRID for 8 days, then two PRIDs for 8 days (0.5-2PRID). Treatment was initiated on the fifth day of the estrous cycle, which was designated as Day 0, and continued for 16 days. All P4-treated females were administered prostaglandin F2alpha on Day 0 and 1 to regress their corpora lutea. Frequency of LH pulses was greater during treatment with the smaller dose of P4 compared with treatment with the larger dose of P4 and the control group. Ovarian follicles were classified into five categories based on ultrasonographic observations: growing (G); atretic (A); growing dominant (GD); growing persistent (GP); or atretic persistent (AP). At ovariectomy on Day 16, the largest and second largest follicles collected were re-classified into five categories based on follicular concentration of steroids. Classification of the largest follicle collected on Day 16 was influenced by treatment (P |
| Databáze: | OpenAIRE |
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