Effect of Estrogen Administration on Endogenous and Luteinizing Hormone-Releasing-Hormone-Induced Luteinizing Hormone Secretion and Follicular Development in the Lactating Sow1
| Autor: | Morag G. Hunter, R. T. Lancaster, G. R. Foxcroft, Shona A. Grant, F. De Rensis |
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| Rok vydání: | 1991 |
| Předmět: |
endocrine system
medicine.medical_specialty Luteinizing hormone secretion medicine.drug_class Cell Biology General Medicine Gonadotropin-releasing hormone Biology Follicular fluid Follicle-stimulating hormone Endocrinology Reproductive Medicine Estrogen Internal medicine Follicular phase medicine Gonadotropin Luteinizing hormone hormones hormone substitutes and hormone antagonists |
| Zdroj: | Biology of Reproduction. 44:975-982 |
| ISSN: | 1529-7268 0006-3363 |
| DOI: | 10.1095/biolreprod44.6.975 |
| Popis: | The objectives of this study were to investigate whether estradiol treatment during lactation modifies 1) the patterns of endogenous LH, FSH, and prolactin (PRL) release; 2) the sensitivity of the pituitary to exogenous injections of LHRH; and 3) the responsiveness of the ovarian follicles to gonadotropin. Plasma LH, FSH, and PRL were determined in samples taken repeatedly from 18 sows on Days 24-27 of lactation. Ovaries were then recovered, and follicular development was assessed by measuring the follicular diameter (FFD) and follicular fluid estradiol-17 beta concentration (FFE) of the ten largest follicles dissected from each ovary. Sows were randomly allocated to one of four treatments: 1) Group C (4 sows) received no treatment; 2) Group LHRH (5 sows) received 800 ng of LHRH every 2 h throughout the sampling period; 3) Group E2 (4 sows) received subcutaneous implants containing estradiol-17 beta 24 h after start of sampling; 4) Group LHRH + E2 (5 sows) were administered a combination of LHRH and estradiol-17 beta implants. Between-animal variability for plasma LH, FSH, and PRL was considerable. LH concentration and LH pulse frequency increased (p less than 0.05) after LHRH treatment in the LHRH and LHRH + E2 groups; however, an acute inhibition of LH secretion was observed in the latter group immediately after estradiol implant application. In the absence of LHRH treatment, estradiol caused chronic inhibition of LH secretion. Follicular development was greater in the LHRH and LHRH + E2 groups compared to the C and E2 groups (p less than 0.05 for both FFD and FFE).(ABSTRACT TRUNCATED AT 250 WORDS) |
| Databáze: | OpenAIRE |
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