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Estradiol Acts Locally Within the Retrochiasmatic Area to Inhibit Pulsatile Luteinizing-Hormone Release in the Female Sheep during Anestrus1
- Source :
- Biology of Reproduction. 56:1544-1549
- Publication Year :
- 1997
- Publisher :
- Oxford University Press (OUP), 1997.
-
Abstract
- In the present study we have identified a site of action of estradiol in the inhibition of LH secretion during anestrus in the ewe. In the first experiment, we studied six sites: the medial preoptic area, the lateral preoptic area, the ventromedial hypothalamus, the ventrolateral hypothalamus, the retrochiasmatic area (RCh), and the periventricular posterior hypothalamus. We compared the changes in parameters of pulsatile LH secretion (interpulse interval, mean nadir, mean amplitude, and mean area under curve) during three 6-h sampling periods: before and 30-36 h and 9 days after intracerebral implantation of crystalline estradiol. Animals that received estradiol in the RCh (n = 5) showed a significantly greater increase in both the intervals between pulses of LH (up 116%, p < 0.03) and the area under the curve (up 180%, p < 0.01) than any of the other groups of 7 animals. In the second experiment, implantation of estradiol in the RCh (n = 6) induced an increase in the intervals between pulses of LH (p < 0.03), whereas receiving an empty implant (n = 6) had no effect, showing that estradiol specifically induced increases in the intervals between pulses. Thus, estradiol appears to act in the RCh where the dopaminergic A15 nucleus, known to inhibit pulsatile LH release, is located.
- Subjects :
- Estrous cycle
medicine.medical_specialty
medicine.drug_class
Dopaminergic
Pulsatile flow
Area under the curve
Cell Biology
General Medicine
Biology
Endocrinology
Reproductive Medicine
Hypothalamus
Estrogen
Internal medicine
medicine
Gonadotropin
Luteinizing hormone
hormones, hormone substitutes, and hormone antagonists
Subjects
Details
- ISSN :
- 15297268 and 00063363
- Volume :
- 56
- Database :
- OpenAIRE
- Journal :
- Biology of Reproduction
- Accession number :
- edsair.doi...........8541ed198456be03809bc775f6045584