Abstract:
:In fish there are few data on the gonadotropin-releasing hormone (Gn-RH) neurosecretory activity, which could explain long- and short-term variations of the gonadotropin secretion. There is no biological species specificity between mammal and fish Gn-RH; although there is a structural difference, they are, on the contrary, characterized by a high immunological specificity which does not allow measurement of fish Gn-RH using radioimmunoassay for LH-RH. We have synthesized salmon Gn-RH according to the formula recently proposed by Sherwood (N. Sherwood, L. Eiden, M. Brownstein, J. Spies, J. Rivier, and W. Vale, 1983. Proc. Natl. Acad. Sci. USA 80, 2794-2798). Its activity has been tested by its ability to stimulate the gonadotropin hormone (GtH) secretion in vivo in testosterone-implanted juvenile rainbow trout, and for the recognition of synthesized Gn-RH (s-Gn-RH) perykaria by a specific antibody raised against the s-Gn-RH in regions of the brain described as containing LH-RH immunoreactive-like material. A radioimmunoassay has been developed for the salmon Gn-RH, and its specificity to measure trout Gn-RH has been tested. Using this assay, the brain and pituitary Gn-RH contents have been measured throughout the final phases of maturation and ovulation. Brain Gn-RH increases from the end of vitellogenesis (8.9 +/- 0.76 ng/brain) to ovulation (more than 15 ng/brain). Pituitary Gn-RH is lower (1.58 +/- 0.69 ng/pituitary) at the end of vitellogenesis and follows a similar profile as in the brain, except for a significant decrease just prior the beginning of oocyte maturation. The correlations between Gn-RH levels and GtH pituitary and plasma levels show that total brain Gn-RH is never correlated to the GtH, suggesting that the increase in the brain Gn-RH content is related to a Gn-RH system closely related to maturation and ovulation, which remains to be investigated. On the contrary, pituitary Gn-RH levels are well correlated with pituitary and plasma GtH levels, indicating that pituitary Gn-RH levels might represent a good index of the Gn-RH neurosecretory activity in the fish hypothalamohypophysial complex, given the absence of a portal system in teleost.
journal_name
Gen Comp Endocrinoljournal_title
General and comparative endocrinologyauthors
Breton B,Motin A,Billard R,Kah O,Geoffre S,Precigoux Gdoi
10.1016/0016-6480(86)90255-8subject
Has Abstractpub_date
1986-01-01 00:00:00pages
109-19issue
1eissn
0016-6480issn
1095-6840journal_volume
61pub_type
杂志文章abstract::Subcutaneous daily injections of ovine prolactin (PRL) inhibit photoperiodic induction of gonads and fattening in the female redheaded bunting (Emberiza bruniceps). However, birds respond to the same photoperiod (15L:9D) after withdrawal of the exogenous PRL. Further, PRL injections given in late hours during the subj...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(83)90127-2
更新日期:1983-11-01 00:00:00
abstract::Thyroid stimulating hormone (TSH) is produced by the anterior pituitary and is used to regulate thyroid hormone output, which in turn controls metabolic activity. Currently, the pituitary is believed to be the only source of TSH used by the thyroid. Recent studies in mice from our laboratory have identified a TSHbeta ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2009.04.006
更新日期:2009-07-01 00:00:00
abstract::The factors influencing prolactin (PRL) variation in birds and in wildlife in general have rarely been investigated with respect to the physiological impacts of exposure to environmental contaminants. We investigated the associations between circulating baseline PRL levels and concentrations of eight persistent organo...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2008.02.013
更新日期:2008-05-01 00:00:00
abstract::This study directly tested the hypothesis that 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) is a goldfish preovulatory pheromone (pheromone released at peak levels during oocyte final maturation) which increases blood gonadotropin (GtH) and milt volume in males. During spontaneous ovulation, GtH and 17,20...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(89)90008-7
更新日期:1989-07-01 00:00:00
abstract::Growth hormones (GHs) and prolactins (Prls) purified from representatives of each vertebrate class from bony fish onwards were tested for their ability to stimulate in vivo peripheral deiodination of labeled thyroxine (T4*) into triiodo-L-thyronine (T3*) in the eel. Plasma T3*/T4* ratio was used as parameter. All GHs ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(89)90091-9
更新日期:1989-02-01 00:00:00
abstract::This study investigates the effects of exogenous thyroxine (T4) on running endurance, tissue masses, and the activities of citrate synthase (CS), pyruvate kinase (PK), cytosolic alpha-glycerophosphate dehydrogenase (alpha-GPDH), and beta-hydroxyacyl Coenzyme A dehydrogenase (HOAD) in Sceloporus undulatus (eastern fenc...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(91)90132-p
更新日期:1991-01-01 00:00:00
abstract::Ecdysteroids play an essential role in the regulation of the molting processes of arthropods. Nuclear receptors of the spider Agelena silvatica that showed high homology with other arthropods especially in the functional domains were identified, two isoforms of ecdysone receptor (AsEcRA, AsEcRB), retinoid X receptor (...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2017.01.032
更新日期:2017-06-01 00:00:00
abstract::Changes in plasma cortisol and glucose concentration were studied in carp during acclimation from fresh water (FW) to 1.5% salt water and vice versa. There was an increase in cortisol and glucose concentration during acclimation from FW to salt water which lasted for several days. Reacclimation to FW did not cause cle...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(84)90155-2
更新日期:1984-06-01 00:00:00
abstract::Day- and nighttime contents of pineal melatonin and other indoleamines were measured in the Chinese hamster, Cricetulus griseus. The hamsters were inbred in our colony and kept in LD 14:10. Absolute levels of pineal melatonin and N-acetylserotonin contents were extremely low, but showed a significant circadian rhythm ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1997.7014
更新日期:1998-01-01 00:00:00
abstract::The insulin-like growth factor (IGF) system in teleosts consists of two ligands, IGF-I and IGF-II, multiple binding proteins, and high-affinity transmembrane receptors. There exists a large gap in our knowledge of the structure and expression of receptors mediating the biological effects of the IGFs in teleosts. For e...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1999.7311
更新日期:1999-08-01 00:00:00
abstract::This study compares follicular function and ovulatory efficiency in 20 sows with obesity/leptin resistance genotype (Iberian pig) and 20 females of lean commercial crosses (Large White × Landrace; LW×L). Estrous cycle was synchronized with progestagens; ovulation was induced with eCG and hCG, in half of the females of...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2010.10.006
更新日期:2011-01-01 00:00:00
abstract::We have found that the inhibition of thyroxine-induced tail fin regression by prolactin in larval tiger salamanders is antagonized by oxytocin. Other workers have shown that prolactin blocks the rise in activity of several hydrolytic enzymes that occurs in regressing tissue during metamorphosis. Here, we examine the e...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(86)90223-6
更新日期:1986-03-01 00:00:00
abstract::The in vitro effects of salmon gonadotropin-releasing hormone (sGnRH), substance P (SP), and their antagonists on prostaglandin F2 alpha (PGF2 alpha), prostaglandin E2 (PGE2), progesterone, androgens, and estradiol-17 beta release by follicles and corpus luteum (CL) of the oviparous lizard, Podarcis sicula sicula, wer...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1994.1018
更新日期:1994-02-01 00:00:00
abstract::To clarify the physiological roles of the renin-angiotensin-aldosterone system (RAAS) and arginine vasotocin (AVT) on body fluid regulation in amphibians, we measured plasma concentrations of aldosterone (ALDO), angiotensin II (ANG II), and AVT after various osmotic challenges in the marine toad, Bufo marinus (Bufonid...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2004.10.005
更新日期:2005-01-15 00:00:00
abstract::In teleosts, lungfish, amphibians, and a reptile, Amphibolurus nuchalis, hormonal stimulation of hepatic glycogenolysis is mediated by a rise in intracellular cyclic AMP concentration. In mammals, by contrast, the inositol trisphosphate/Ca2+/diacylglycerol signal transduction pathways are also involved. The present st...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(92)90200-4
更新日期:1992-10-01 00:00:00
abstract::Current views on Agnathan phylogeny favor the hypothesis that the genera of holarctic lampreys belong to a single family (Petromyzontidae) and form an interrelated progression in which Petromyzon is near to Ichthomyzon at the base of the phylogenetic tree and Lampetra is the most derived. A stock similar to that of co...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1998.7203
更新日期:1999-02-01 00:00:00
abstract::The neuroendocrine light green cells (LGCs) control body growth and metabolism of the freshwater snail, Lymnaea stagnalis. These cells, located in the cerebral ganglia, use the peripheries of the median lip nerves (MLNs) as the neurohemal area. The LGCs express four members of a gene family encoding the precursors of ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(92)90152-a
更新日期:1992-07-01 00:00:00
abstract::Aromatase is the key enzyme for estrogen biosynthesis and is encoded by Cyp19 gene. Placental cotyledons are the main site of Cyp19 gene expression during pregnancy. The present study was aimed to investigate if DNA methylation and thus epigenetic mechanisms play a potential role in stage-specific regulation of Cyp19 ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2010.07.012
更新日期:2010-11-01 00:00:00
abstract::Homogenates of maturing rainbow trout testes show specific binding sites for 125J-labeled hCG (= 125I-labeled hCG). The binding is competitively inhibited by unlabeled hCG and by a hypophyseal extract of rainbow trout. It could be demonstrated that the tissue 125J-hCG binding specificity is restricted to the gonadal p...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(83)90143-0
更新日期:1983-02-01 00:00:00
abstract::The present study was undertaken to characterize different vitellogenins in Channa punctatus. Protein purification by gel chromatography followed by fast protein liquid chromatography (FPLC) revealed existence of two different Vg forms. Liquid chromatography tandem mass spectrophotometry (LC-MS/MS) suggested the exist...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2013.05.002
更新日期:2013-08-01 00:00:00
abstract::Melatonin and arylalkylamine N-acetyltransferase (AANAT), the rate-limiting enzyme in melatonin synthesis, have taken on special importance in vertebrate circadian biology. Recent identification of genes encoding two AANAT (AANAT(1) and AANAT(2)) and two subtypes of melatonin receptor (Mel-R; Mel(1a) and Mel(1b)) in s...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2004.01.004
更新日期:2004-05-01 00:00:00
abstract::A specific polyclonal antiserum directed against the somatostatin-28(1-14) of vertebrates was applied to sections of the planarians Dugesia lugubris and Dendrocoelum lacteum. This made it possible to reveal nerve cells and processes specifically both in cerebral ganglia and in ventral nerve cords. The phylogenetic imp...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(90)90035-k
更新日期:1990-06-01 00:00:00
abstract::The presence of binding sites for nonecdysteroid steroids was investigated in the cytosol of several tissues of the migratory locust, Locusta migratoria migratorioides. Binding of androgens was not observed. Most tissues, however, showed nonsaturable binding of estrogens and in some tissues saturable progestin binding...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(88)90162-1
更新日期:1988-12-01 00:00:00
abstract::The administration of arginine vasotocin (AVT) to gravid snapping turtles with steroidogenically active corpora lutea and high plasma progesterone concentration (1480 +/- 155 pg/ml) did not trigger oviposition, whereas 12 days after ovulation when luteolysis occurred and plasma progesterone concentration was low (570 ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(88)90052-4
更新日期:1988-01-01 00:00:00
abstract::Biologically active recombinant yellowtail kingfish follicle stimulating hormone (rytkFsh) was produced in yeast Pichia pastoris and its biological activity was demonstrated by both in-vitro and in-vivo bioassays. Incubation of ovarian and testicular fragments with the recombinant hormone stimulated E2 and 11-KT secre...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2016.03.001
更新日期:2017-01-15 00:00:00
abstract::Dopamine (DA) has a pivotal role in avian prolactin (PRL) secretion, acting centrally through D(1) DA receptors to stimulate PRL secretion by operating through vasoactive intestinal peptide (VIP). DA also inhibits PRL secretion by activating D(2) DA receptors at the pituitary level. This study was designed to investig...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2008.08.002
更新日期:2008-10-01 00:00:00
abstract::The copepod Calanus finmarchicus is the most abundant zooplankton species in the North Atlantic. While the life history of this crustacean is well studied, little is known about its peptidergic signaling systems despite the fact that these pathways are undoubtedly important components of its physiological/behavioral c...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2013.03.018
更新日期:2013-06-15 00:00:00
abstract::Oligonucleotide probes were synthesized for the mRNAs of a pair of tilapia prolactins (tPRL177 and tPRL188) and growth hormone (tGH) based on cDNAs for the hormones of Oreochromis niloticus and amino acid sequences for the hormones of O. mossambicus. The three 45mer probes were labeled with 35S for hybridization studi...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1993.1010
更新日期:1993-01-01 00:00:00
abstract::The rainbow trout (Oncorhynchus mykiss) ovarian gonadotropin (GTH II) receptor was solubilized by extraction with the nonionic detergent 1% Triton X-100 in the presence of 20% glycerol. The hormone-binding characteristics of the soluble receptors were similar to those of membrane-bound receptors: the Scatchard plot of...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1993.1127
更新日期:1993-09-01 00:00:00
abstract::Sexual dimorphism in prenatal development is widespread among vertebrates, including birds. Its mechanism remains unclear, although it has been attributed to the effect of maternal steroid hormones. The aim of this study was to investigate how increased levels of steroid hormones in the eggs influence early embryonic ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2017.09.004
更新日期:2017-12-01 00:00:00