Abstract:
:The presence and distribution of cholecystokinin (CCK)/gastrin-like immunoreactivity (IR) was examined in the goldfish pituitary. Intense CCK/gastrin-like IR was consistently observed within fibers of the proximal pars distalis (PD), with fewer IR fibers localized in the rostral PD. Within the proximal PD CCK/gastrin-like IR fibers were distributed among both the gonadotrophs and somatotrophs, suggesting a possible role for CCK-like peptides in the regulation of gonadotropin-II (GtH-II) and growth hormone (GH) secretion. Exposure of pituitary fragments from either sexually gonadal recrudescing (maturing) or regressed goldfish to three 5-min pulses of 1.0 or 10 nM sulfated CCK8 (CCK8-s), at 55-min interpulse intervals, resulted in an increased secretion of both GtH-II and GH. Independent of the dose perifused, the GtH-II release responses to the second and third pulses of CCK8-s were always of similar magnitude to the first pulse at a given dose. For GH, repeated challenges of pituitary fragments to 0.1 or 1.0 nM CCK8-s stimulated release responses of similar magnitude; however, successive pulses of 10 nM CCK8-s resulted in a desensitization in the GH release response to the second or the third pulse. Fragments from sexually regressed goldfish exhibited an overall greater release response of GtH-II to CCK8-s relative to fragments from sexually recrudescing fish, whereas the GH release responses to CCK8-s were similar between the two sexual stages. A dose-dependent release of GtH-II was present in pituitary fragments from sexually regressed goldfish following five 5-min pulses of increasing (0.1 to 100 nM) doses of CCK8-s. Finally, the sulfated forms of CCK8 and gastrin 17 (G17-s) exhibited greater stimulatory abilities than the nonsulfated form of CCK8 in releasing GtH-II and GH from fragments of sexually recrudescing fish. Additionally, CCK8-s and G17-s were equal in their capacity to stimulate the release of GtH-II, whereas G17-s was slightly more effective than CCK8-s in stimulating the release of GH. Overall, these studies are the first to provide evidence that IR CCK/gastrin-like fibers are codistributed among the gonadotrophs and somatotrophs, and that CCK-like peptides are highly effective in stimulating GtH-II and GH release from the goldfish pituitary.
journal_name
Gen Comp Endocrinoljournal_title
General and comparative endocrinologyauthors
Himick BA,Golosinski AA,Jonsson AC,Peter REdoi
10.1006/gcen.1993.1146subject
Has Abstractpub_date
1993-10-01 00:00:00pages
88-103issue
1eissn
0016-6480issn
1095-6840pii
S0016-6480(83)71146-9journal_volume
92pub_type
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journal_title:General and comparative endocrinology
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journal_title:General and comparative endocrinology
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journal_title:General and comparative endocrinology
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journal_title:General and comparative endocrinology
pub_type: 杂志文章
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journal_title:General and comparative endocrinology
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journal_title:General and comparative endocrinology
pub_type: 杂志文章
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journal_title:General and comparative endocrinology
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journal_title:General and comparative endocrinology
pub_type: 杂志文章,评审
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更新日期:2009-09-01 00:00:00
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journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.2001.7628
更新日期:2001-06-01 00:00:00
abstract::Reproductive maturation and regulation is centrally orchestrated by gonadotropin-releasing hormone (GnRH). GnRH produced in the vertebrate hypothalamus acts on the pituitary to regulate gonadotropins. In nonplacental mammalian species, it has recently been shown that a second GnRH gene is expressed in mesencephalic ce...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1996.0135
更新日期:1996-10-01 00:00:00
abstract::This experiment was performed on two groups of male Japanese quail. One had been maintained in our laboratory as a closed colony (S-group), and the other had been obtained from a commercial source (R-group). Different responses of gonadal function were found between two groups following either testosterone treatment o...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(85)90390-9
更新日期:1985-09-01 00:00:00
abstract::In order to delineate further the molecular evolution of the renin-angiotensin system in vertebrates, angiotensin I (ANG I) has been isolated after incubation of plasma and kidney extracts of emu (Dromiceus novaehollandiae), axolotl (Ambystoma mexicanum), and sea lamprey (Petromyzon marinus). The identified sequences ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2003.10.011
更新日期:2004-02-01 00:00:00