Abstract:
:The frequency of pulsatile release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) is high in the breeding season and low in the nonbreeding season. These alterations in the patterns of GnRH and LH release are due to an interaction of daylength and gonadal steroid negative feedback. A vast amount of data indicates that steroid-responsive neural systems may play a role in regulating seasonal changes in GnRH release. One candidate system is neuropeptide Y (NPY). To determine the independent and interactive influences of photoperiod and steroid exposure on NPY mRNA levels, we used hypothalamic tissue from four groups (n = 4 per group) of castrated male sheep that were simultaneously housed in photochambers and exposed to: (1) a 16L:8D photoperiod (LD); (2) LD and implanted with testosterone (LD + T); (3) a 10L:14D photoperiod (SD), and (4) SD + T. Circulating levels of T averaged 2.8 +/- 0.2 ng/ml in implanted animals, but were undetectable in nonimplanted males. Mean LH levels were significantly reduced (p < 0.01) in the LD + T group as compared with the other groups which did not differ from each other. The silver grain area per NPY neuron in the arcuate nucleus, as assessed by in situ hybridization, was inversely related to mean LH values, with the grain area per cell being significantly greater (p < 0.05) for LD + T males than for all other groups which did not differ from each other. NPY cell numbers were not significantly different (p > 0.10) among the treatment groups. These results show that NPY mRNA expression is increased in male sheep during a LD photoperiod in a T-dependent manner. Our data are consistent with the idea that NPY is involved in the seasonal regulation of GnRH and LH release in the male sheep.
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Dobbins A,Lubbers LS,Jackson GL,Kuehl DE,Hileman SMdoi
10.1159/000076631subject
Has Abstractpub_date
2004-02-01 00:00:00pages
82-9issue
2eissn
0028-3835issn
1423-0194pii
76631journal_volume
79pub_type
杂志文章abstract::The pressor effect of intravenous angiotensin II (AII) was compared in the unrestrained rat before and after electrolytic lesions of the subfornical organ (SFO), the circumventricular organ of the dorsal third cerebral ventricle. Abdominal aortic and venal caval catheters were used to measure arterial pressure and to ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
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journal_title:Neuroendocrinology
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doi:10.1159/000122372
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:1992-07-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000332128
更新日期:2012-01-01 00:00:00
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journal_title:Neuroendocrinology
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更新日期:2018-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000350790
更新日期:2013-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126381
更新日期:1993-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126372
更新日期:1993-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125111
更新日期:1989-02-01 00:00:00
abstract::This study was carried out to clarify the central effects of neuropeptide Y (NPY) on gonadotropin and prolactin (PRL) release in the male rat and to evaluate the hypothesis that it may play a role in negative feedback regulation of gonadotropin secretion in the male. NPY (4 micrograms in 2 microliters 0.9% NaCl) or an...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126481
更新日期:1993-06-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126605
更新日期:1993-12-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124108
更新日期:1985-05-01 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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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000363367
更新日期:2014-01-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126799
更新日期:1994-12-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123586
更新日期:1983-12-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000092521
更新日期:2005-01-01 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:10.1159/000054402
更新日期:1999-01-01 00:00:00
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更新日期:2018-01-01 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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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123594
更新日期:1983-12-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126466
更新日期:1993-06-01 00:00:00
abstract::A prolactin (PRL) surge occurs in the female rat during proestrus in response to elevated estradiol levels. The elevated release of ovarian steroids on the day of proestrus is also associated with sexual receptivity. Mating triggers twice-daily PRL surges that supplant the proestrous PRL surge and are responsible for ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000054429
更新日期:1999-04-01 00:00:00
abstract::The neuroanatomical distribution and morphology of neurons that produce gonadotropin-releasing hormone (GnRH) in the brain of the postpubertal male Djungarian hamster was studied using light microscopic immunocytochemistry. Analysis of every section from the rostral olfactory tubercle to the medial basal hypothalamus ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125341
更新日期:1990-02-01 00:00:00
abstract::It is now well documented that various polyclonal antisera to the human growth hormone-releasing factor (hGHRF, somatocrinin) visualize in the brain by immunohistochemistry the classical hypothalamic hypophysiotropic neurons and also antigens present in otherwise characterized peptidergic neuronal systems. The nature ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125370
更新日期:1990-04-01 00:00:00
abstract::Recent studies have shown that primary hypothyroidism induced in the rat was able to stimulate the biosynthesis of vasoactive intestinal peptide (VIP) in the anterior pituitary (AP). Since the AP VIP is known to stimulate prolactin (PRL) secretion through a paracrine and/or autocrine mechanism, it is interesting to hy...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000126842
更新日期:1995-02-01 00:00:00
abstract::The developmental pattern of hypophyseal luteinizing hormone (LH) during fetal and early postnatal life, and the capacity of fetal and early postnatal pituitaries to synthesize, release and store LH in the absence of any hypothalamic influence were investigated. Pituitary radioimmunoassayable LH was detectable by feta...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123923
更新日期:1984-05-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000507761
更新日期:2020-04-08 00:00:00
abstract::Although previously considered rare, recent epidemiological studies have revealed that the incidence (3.6/100,000) and prevalence (35/100,000) of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) has increased over the past few decades. Despite the progress in the understanding of GEP-NET molecular biology, ther...
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pub_type: 杂志文章,评审
doi:10.1159/000362339
更新日期:2014-01-01 00:00:00