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Ovulatory Response, and Plasma Concentrations of Luteinizing Hormone and Progesterone Following Administration of Synthetic Mammalian or Chicken Luteinizing Hormone-Releasing Hormone Relative to the First or Second Ovulation in the Sequence of the Domestic Hen
- Source :
- Biology of Reproduction. 31:646-655
- Publication Year :
- 1984
- Publisher :
- Oxford University Press (OUP), 1984.
-
Abstract
- Experiments were conducted to investigate hypophyseal and follicular competency at two distinct stages of the hen's egg laying sequence: 1) 14 h prior to the first (C1) ovulation of a sequence (27 h following the previous ovulation); and 2) 14 h prior to the second (C2) ovulation of a sequence (13 h following the previous ovulation). When a single dose of mammalian luteinizing hormone-releasing hormone (mLHRH) or chicken luteinizing hormone-releasing hormone (cLHRH) was injected 14 h prior to a C1 ovulation, premature ovulation was induced in 19 of 20 hens. In contrast, ovulation was premature in only 1 of 20 hens when mLHRH or cLHRH was injected 14 h prior to a C2 ovulation. There was no difference between the two stages of the sequence in the amount of luteinizing hormone (LH) released for up to 60 min following a single i.v. injection of 20 micrograms mLHRH. However, only prior to a C1 ovulation did LH levels further increase to reach preovulatory concentrations. By contrast, progesterone (P4) concentrations were increased within the first 60 min to a lesser extent in hens injected prior to a C2 ovulation compared to a C1 ovulation. In C2-injected birds, P4 fell to levels that were not different from vehicle-injected controls by 45 to 60 min following injection, whereas P4 secretion was maintained in hens injected prior to a C1 ovulation. We suggest that the lack of sustained LH secretion following treatment with either species of LHRH 14 h prior to a C2 ovulation is related to follicular immaturity with respect to ability to produce and secrete P4. At the dosage administered, there was no difference in the ability of mLHRH compared to cLHRH to release LH at either stage of the sequence. Finally, two successive injections of mLHRH at 14 and 13 h prior to a C2 ovulation induced premature ovulation in 6 of 11 hens. It is suggested that LH, and possibly P4, exerts a priming effect on the largest preovulatory follicle to initiate fully potentiated P4 production and secretion.
- Subjects :
- Ovulation
medicine.medical_specialty
Time Factors
media_common.quotation_subject
Gonadotropin-releasing hormone
Biology
Gonadotropin-Releasing Hormone
Follicle
Internal medicine
Follicular phase
medicine
Animals
Secretion
Progesterone
media_common
Cell Biology
General Medicine
Luteinizing Hormone
Endocrinology
Reproductive Medicine
Plasma concentration
Female
Luteinizing hormone
Chickens
Hormone
Subjects
Details
- ISSN :
- 15297268 and 00063363
- Volume :
- 31
- Database :
- OpenAIRE
- Journal :
- Biology of Reproduction
- Accession number :
- edsair.doi.dedup.....9f714b2c859adf6fdd7b84b0b6400134