Abstract:
:To assess whether gonadotropin-releasing hormone (GnRH) release from the hypothalamus might be altered by hyperprolactinemia in the male rat, we measured in chronically hyperprolactinemic rats the pituitary GnRH receptor content and described the pattern of luteinizing hormone (LH) release during the postcastration rise in gonadotropin secretion 24 and 72 h after gonadectomy. In intact rats, the effect of hyperprolactinemia was determined by describing the pattern of LH secretion, pituitary GnRH receptor content and assessment of pituitary responsiveness to small doses of GnRH (1.0 ng). In addition, to determine the role endogenous opioids might play in inhibiting GnRH release in hyperprolactinemic rats, we examined the effect of both a continuous infusion and a bolus injection of the opioid antagonist naloxone on the pattern of LH release. Chronic hyperprolactinemia was achieved by implanting 4 pituitaries under the kidney capsules 3-4 weeks before study. Acute hyperprolactinemia was achieved by injecting rats with 1 mg ovine prolactin every 12 h for 3 days. Control animals were untreated or were chronically hyperprolactinemic rats in which the hyperprolactinemia was transiently reversed by treatment for 3 days with the dopamine agonist 2-alpha-bromoergocryptine. The mean LH concentration was greatly decreased at 24 postcastration in chronically hyperprolactinemic rats relative to controls. This decrease was associated with a decrease in LH pulse height and pulse amplitude and pituitary GnRH receptor content, but not with an increase in the LH interpulse interval. In contrast, the decrease in mean LH concentrations in hyperprolactinemic animals at 72 h postcastration was primarily associated with a significantly longer LH interpulse interval than that observed in control animals. Chronic hyperprolactinemia in intact rats decreased the pituitary GnRH receptor content, in addition to decreasing the mean LH concentrations during pulsatile GnRH administration. Chronic hyperprolactinemia also inhibited LH release relative to controls during the continuous 4-hour infusion of naloxone and in response to a bolus injection of naloxone. However, in acutely hyperprolactinemic intact male rats a bolus injection of naloxone increase LH secretion 20 min later to levels similar to those obtained in control rats. In summary, these results indicate that chronic hyperprolactinemia decreased LH secretion by primarily decreasing GnRH secretion as suggested by a decrease in pituitary GnRH receptor content and a decrease in LH pulse frequency and pulse amplitude.(ABSTRACT TRUNCATED AT 400 WORDS)
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Fox SR,Hoefer MT,Bartke A,Smith MSdoi
10.1159/000124844subject
Has Abstractpub_date
1987-10-01 00:00:00pages
350-9issue
4eissn
0028-3835issn
1423-0194journal_volume
46pub_type
杂志文章abstract::Visual average evoked responses (AERs) to 4 intensities of light were studied in 5 patients with adrenal cortical insufficiency. Patients were tested off all medications, on ACTH while off all medications, and during replacement with carbohydrate-active steroids. Off treatment, when steroid levels were low, AERs were ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122452
更新日期:1975-01-01 00:00:00
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journal_title:Neuroendocrinology
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更新日期:1997-04-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000127039
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125531
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pub_type: 杂志文章
doi:10.1159/000125617
更新日期:1990-10-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
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更新日期:1987-02-01 00:00:00
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更新日期:1985-05-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125724
更新日期:1991-03-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124463
更新日期:1986-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123067
更新日期:1980-08-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124822
更新日期:1987-09-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122674
更新日期:1977-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125348
更新日期:1990-03-01 00:00:00
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pub_type: 杂志文章
doi:10.1159/000054417
更新日期:1999-03-01 00:00:00
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pub_type: 杂志文章
doi:10.1159/000122974
更新日期:1980-01-01 00:00:00
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pub_type: 杂志文章
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更新日期:1977-01-01 00:00:00
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pub_type: 杂志文章
doi:10.1159/000054474
更新日期:1999-09-01 00:00:00
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pub_type: 杂志文章
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更新日期:1986-01-01 00:00:00
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journal_title:Neuroendocrinology
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doi:10.1159/000124188
更新日期:1985-09-01 00:00:00
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更新日期:2019-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124846
更新日期:1987-10-01 00:00:00
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更新日期:1998-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
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更新日期:1989-10-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122841
更新日期:1979-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
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更新日期:1986-01-01 00:00:00
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pub_type: 杂志文章
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更新日期:1981-06-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
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更新日期:1979-01-01 00:00:00