Abstract:
:The effects of salmon gonadotropin-releasing hormone (sGnRH) and the superactive agonist [D-Arg6, Pro9NEt]-sGnRH (sGnRH-A) on growth hormone (GH) and gonadotropin (GtH) release were examined using a perifusion system for pituitary fragments of the common carp (Cyprinus carpio). Perifusion of 2-min pulses of different concentrations of sGnRH or sGnRH-A stimulated a rapid and dose-dependent increase in GH release: ED50 values for sGnRH and sGnRH-A in stimulating GH release were 2.8 +/- 0.7 and 0.5 +/- 0.1 nM, respectively, indicating that the superactivity of sGnRH-A for stimulation of GtH release also applies in induction of GH release. Exposure of the pituitary fragments to 10 nM sGnRH or sGnRH-A alone resulted in increases in GH and GtH release on a similar temporal course. Apomorphine (10, 100, and 1000 nM) significantly inhibited basal and GnRH-induced GtH release in a dose-dependent manner and significantly stimulated basal GH release; however, APO did not enhance GnRH-induced GH release. Somatostatin (100 nM) significantly blocked basal release and 10 nM sGnRH- and sGnRH-A-induced GH release, but was ineffective on GtH release. Treatment with somatostatin (100 nM) in combination with apomorphine (100 nM) caused an increase in sGnRH-induced GH release compared to treatment with somatostatin alone; whereas, on GtH there was a significant decrease in basal and GnRH-induced levels, compared to treatment with somatostatin alone. These results indicate that GH release in common carp is regulated by somatostatin as GH release inhibitor. sGnRH and sGnRH-A act as GH-releasing factors; the mechanisms by which GnRH stimulates GH and GtH secretion are independent. The dopamine agonist apomorphine stimulates GH release and inhibits GtH release directly at the pituitary level.
journal_name
Gen Comp Endocrinoljournal_title
General and comparative endocrinologyauthors
Lin XW,Lin HR,Peter REdoi
10.1006/gcen.1993.1009subject
Has Abstractpub_date
1993-01-01 00:00:00pages
62-71issue
1eissn
0016-6480issn
1095-6840pii
S0016-6480(83)71009-9journal_volume
89pub_type
杂志文章abstract::Acute pancreatic hormonal responses to oral glucose loads were investigated in garden warblers during the prolonged fast that follows their autumnal migratory fattening. Plasma glucose, free fatty acids, beta-hydroxybutyrate, insulin (INS), and glucagon (GLN) were measured prior to and 10 min after an oral glucose loa...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1999.7295
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abstract::Like IGF-I, progranulin (pgrn) is a growth factor involved in tumorigenesis and wound healing. We report here the identification and characterization of pgrn cDNA in tilapia and the regulation of its expression by growth hormone (GH). The tilapia pgrn cDNA was cloned by RT-PCR amplification, using gene specific oligon...
journal_title:General and comparative endocrinology
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journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1994.1012
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journal_title:General and comparative endocrinology
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pub_type: 杂志文章,评审
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journal_title:General and comparative endocrinology
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abstract::The total cortisol content in tilapia was 55 pg immediately following fertilization, then decreased abruptly and maintained a lower level of 10-20 pg until hatching; after hatching the cortisol content increased to 50 pg by the 7th day. Fertilized eggs were incubated in either 32% saltwater or fresh water and sampled ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1993.1168
更新日期:1993-11-01 00:00:00
abstract::Red deer stags have a seasonal pattern of growth, alternating between periods of summer weight gain and winter weight loss that are influenced by photoperiod and by exogenous melatonin. A seasonal pattern of plasma insulin-like growth factor 1, also influenced by photoperiod, underlies the seasonal growth pattern. The...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(92)90156-e
更新日期:1992-07-01 00:00:00
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journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(91)90167-5
更新日期:1991-03-01 00:00:00
abstract::The relations among rearing environment, fish size, insulin-like growth factor-I, and smoltification were examined in yearling spring chinook salmon (Oncorhynchus tshawytscha). Juvenile chinook salmon were size-graded into small and large categories. Half of the fish in each group were reared at an increased temperatu...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1997.7036
更新日期:1998-03-01 00:00:00
abstract::The dynamics of androgen production by perfused Xenopus testis explants has been investigated under various gonadotropic stimulations. Androgens were measured in perfusate by radioimmunoassay. The behavior of hormones in the perfusion system was assessed. Pieces of testis were capable of producing androgens after more...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(83)90057-6
更新日期:1983-09-01 00:00:00
abstract::We have examined the effect of ambient water temperature on the ability of juvenile rainbow trout to respond to estradiol (E2) injection with vitellogenin (Vg) synthesis. Vg appeared in serum within 24 hr of E2 injection in fish kept at 15 degrees and rose to 70 mg/ml over a 10-day treatment period during which four i...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1993.1031
更新日期:1993-02-01 00:00:00
abstract::The aim of our study was to confirm the role of tidal pattern on the coordination of oocyte maturation and spawning in common snook Centropomus undecimalis. To do so, we studied oocyte maturation during the spawning season in relation to the tidal pattern in both males and females by means of histology and hormonal pr...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2015.08.007
更新日期:2015-12-01 00:00:00
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journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2003.12.020
更新日期:2004-04-01 00:00:00
abstract::The avian neurohypophyseal hormone arginine vasotocin (AVT) is known to be involved in the regulation of adrenocorticotropin (ACTH) release by interacting with the VT2 receptor (VT2R), which is homologous to the mammalian vasopressin V1b receptor (V1bR). To study the role of glucocorticoid in the expression and regula...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2008.12.019
更新日期:2009-04-01 00:00:00
abstract::The present investigation was designed to (1) determine if atrial natriuretic factor gene expression occurs within invertebrates as well as within vertebrates; (2) determine whether the product of this gene expression is the 126-amino-acid atrial natriuretic factor prohormone or some other molecular species; and (3) e...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1995.1133
更新日期:1995-10-01 00:00:00
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journal_title:General and comparative endocrinology
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abstract::In in vivo experiments injection of dopamine (DA) or leucine enkephalin (L-Enk) produced hypoglycemia in intact red swamp crayfish, Procambarus clarkii. In contrast, neither compound had a significant effect on the circulating glucose concentration in eyestalkless individuals. With intact crayfish spiperone, a DA rece...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
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更新日期:1995-01-01 00:00:00
abstract::Our previous study showed the seasonal variations in expression of vasotocin (VT) and isotocin (IT) genes in preoptic magnocellular neurons of female masu salmon (Oncorhynchus masou). The changes in the level of VT mRNA were coincident with those in plasma testosterone and estradiol levels. In the present study, gener...
journal_title:General and comparative endocrinology
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doi:10.1006/gcen.1999.7344
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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
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abstract::Insulin receptor downregulation in the isolated hepatocytes of lamprey (Lampetra fluviatilis) was studied at the ambient temperature for this species. Preincubation of hepatocytes with 10(-9)-10(-8) M unlabeled insulin decreased insulin binding capacity to 43, 37, and 34% at 4, 15, and 25 degrees, respectively. Preinc...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
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