Abstract：
:This study investigated the role of gonadotrophin and steroids in the induction of in vitro oocyte maturation in dab (Limanda limanda) and plaice (Pleuronectes platessa), two marine flatfish (Pleuronectiformes) in which the oocytes mature and ovulate in groups (or batches). Clusters of folliculated oocytes were incubated for 3 days with a range of doses of either human chorionic gonadotrophin (HCG) or synthetic steroids with a wide range of structures. They were also incubated with extracts from cultures of HCG-stimulated ovaries. Oocytes were always more responsive to HCG than to steroids, and the median efficient doses obtained with HCG were negatively correlated with oocyte diameters. Bioassay sensitivity to steroids was low when compared with other teleosts, and intraassay variability was high, particularly in plaice. Despite the high variability, a common pattern in specificities to steroids was obtained for the two species, which was also similar to other teleost species. Among the most effective steroids found were 17 alpha,20 beta-dihydroxy-4-pregnen-3-one and 17 alpha,20 beta,21-trihydroxy-4-pregnen-3-one. Extracts from incubates were ineffective. The significance of these findings and possible ways to reduce assay variability and improve sensitivity are discussed.
journal_name
Gen Comp Endocrinoljournal_title
General and comparative endocrinologyauthors
Canario AV,Scott APdoi
10.1016/0016-6480(90)90301-2subject
Has Abstractpub_date
1990-02-01 00:00:00pages
161-76issue
2eissn
0016-6480issn
1095-6840journal_volume
77pub_type
杂志文章abstract：:Fish egg yolk is largely derived from vitellogenins, which are synthesized in the liver, taken up from the maternal circulation by growing oocytes via receptor-mediated endocytosis and enzymatically processed into yolk proteins that are stored in the ooplasm. Lipid droplets are another major component of fish egg yolk...
journal_title：General and comparative endocrinology
pub_type： 杂志文章,评审
doi：10.1016/j.ygcen.2015.01.025
更新日期：2015-09-15 00:00:00
abstract：:The presence of cholecystokinin (CCK), originally isolated from porcine small intestine, has been reported in a diversity of invertebrates ranging, from cnidarians to protochordates, but so far, not in echinoderms. We have used immunohistochemical techniques to demonstrate the presence of cells expressing CCK-like imm...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(91)90026-3
更新日期：1991-08-01 00:00:00
abstract：:We investigated the development of thyroid function during the transition to endothermy in red-winged blackbirds (Agelaius phoeniceus). Thermoregulatory capabilities of blackbirds improve markedly over their relatively short nestling period (10-12 days), with the most striking improvements occurring between days 6 and...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1999.7363
更新日期：1999-11-01 00:00:00
abstract：:Naked mole rats seem to be naturally deficient in cholecalciferol yet exhibit net calcium and inorganic phosphorus absorption efficiencies that approach a physiological maximum (i.e., exceed 94%). Oral supplementation with cholecalciferol therefore does not markedly enhance the efficiency of gastrointestinal absorptio...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1993.1019
更新日期：1993-01-01 00:00:00
abstract：:Chickens have blood glucose concentrations that are twofold higher than those observed in mammals. Moreover, the insulin sensitivity seems to decrease with postnatal age in both broiler and layer chickens. However, little is known about the response of insulin on plasma glucose concentrations and mRNA abundance of hep...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2015.12.026
更新日期：2016-06-01 00:00:00
abstract：:In the last two decades, maternally derived yolk androgens have been shown to significantly alter offspring development, and a number of these effects persist into adulthood. However, little is known about their underlying mechanisms. Mechanisms that have been suggested are changes in the endogenous androgen productio...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2013.10.014
更新日期：2014-01-01 00:00:00
abstract：:Growing evidence shows that sex steroids not only act within the individual whose glands produce them; they can also act on proximate conspecifics. Previous studies show that exogenous 17β-estradiol (E2) can be absorbed both nasally and percutaneously, arriving in blood, neural, reproductive, and peripheral tissues. W...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2019.113321
更新日期：2020-01-15 00:00:00
abstract：:A gonadotropin-releasing hormone (GnRH) agonist, d-Trp6-LHRH, was evaluated for its effectiveness in reducing circulating testosterone concentrations in wild Hawaiian monk seals (Monachus schauinslandi). Twenty-eight adult male seals were randomly divided into three groups: 10 were captured and treated with 7.5 mg of ...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1998.7173
更新日期：1998-11-01 00:00:00
abstract：:To study the expression of four estrogen receptor genes (erα1, erα2, erβ1, erβ2) of female rainbow trout (Oncorhynchus mykiss) during first ovarian development, trouts were sampled from different ovarian stages. Serum E2 (estradiol) was measured by ELISA and estrogen receptors mRNA expression were examined by qRT-PCR....
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2017.10.001
更新日期：2018-04-01 00:00:00
abstract：:In Sphaeroma serratum, the differentiation of the male external sexual characteristics, as a result of an androgenic gland implant, proceeds more easily in females in vitellogenesis than in immature females. On the contrary, the transformation of the gonads is quicker and more obvious in immature females than in matur...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(83)90250-2
更新日期：1983-04-01 00:00:00
abstract：:The reproductive biology of the Indian major carp Cirrhinus mrigala is tightly synchronized with the seasonal changes in the environment. While the ovaries show growth from February through June, the fish spawn in July-August to coincide with the monsoon; thereafter the fish pass into the postspawning and resting phas...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/s0016-6480(03)00190-4
更新日期：2003-10-01 00:00:00
abstract：:A brief description is given of the discovery of PTHrP and the roles of the peptide in mammalian physiology. Next, the occurrence of PTHrP in the earliest vertebrates, sharks, skates and fishes, is reviewed and the calciotropic functions of PTHrP are addressed more specifically in fishes. Parathyroid hormone-related p...
journal_title：General and comparative endocrinology
pub_type： 杂志文章,评审
doi：10.1016/j.ygcen.2006.11.010
更新日期：2007-06-01 00:00:00
abstract：:Avian reproduction entails complex endocrine interactions at the hypothalamic and ovarian levels. The initiation of the reproductive season is due to the reduction in melatonin and GnIH production as day length increases. The decline in GnIH permits GnRH and gonadotropin secretion starting follicle growth. Follicular ...
journal_title：General and comparative endocrinology
pub_type： 杂志文章,评审
doi：10.1016/j.ygcen.2014.03.040
更新日期：2014-07-01 00:00:00
abstract：:Asp1,Val5-angiotensin II (AII) caused dose-dependent increases in aortic blood pressure (BP) when injected into anesthetized Pekin ducks. Norepinephrine (NE) and epinephrine (E) concentrations in arterial plasma were found to be elevated 1 min after injection of AII, when BP was peaking, while plasma levels of unconju...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(83)90065-5
更新日期：1983-09-01 00:00:00
abstract：:The hypothesis that vasoactive intestinal peptide (VIP) functions as a hypothalamic prolactin (PRL)-releasing peptide in the turkey was tested by determining the effects of hypothalamic VIP immunoneutralization and pituitary VIP receptor blockade on hypothalamic extract (HE)-induced PRL secretion from dispersed anteri...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(90)90048-q
更新日期：1990-04-01 00:00:00
abstract：:An earlier study reported that blinding or exposure to red light stimulates reproduction in R. cyanophlyctis. The present study investigates whether melatonin counteracted blinding- or red-light-induced ovarian stimulation. The study consisted of two experiments carried out during the prebreeding (March/April) and bre...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1999.7443
更新日期：2000-04-01 00:00:00
abstract：:In rainbow trout, a variable in vivo pituitary sensitivity to GnRH has been previously observed, depending on the stage of oogenesis. The purpose of the present work was to study, in vitro, the role of oestradiol (E2) and 17 alpha-hydroxy,20 beta-dihydroprogesterone (17 alpha 20 beta P), respectively, involved in vite...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(90)90079-2
更新日期：1990-09-01 00:00:00
abstract：:The box turtle (Terrapene carolina triunguis) does not appear to have evolved a mechanism for secondary bone formation similar to Aves inasmuch as several parameters of bone calcium metabolism were unaffected by estrogen treatment. This suggests that reproduction does not constitute a substantial stress to the calcium...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(84)90212-0
更新日期：1984-04-01 00:00:00
abstract：:Cholesterol transport across the mitochondrial membrane is rate-limiting for steroidogenesis in vertebrates. Previous studies in fish have characterized expression of the steroidogenic acute regulatory protein, however the function and regulation of other genes and proteins involved in piscine cholesterol transport ha...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2011.04.027
更新日期：2011-08-01 00:00:00
abstract：:Interrenal tissue from embryonic and larval rainbow trout (Oncorhynchus mykiss) was cultured in vitro and exposed to various doses of adrenocorticotropin (ACTH) to document the ontogeny of interrenal responsiveness to tropic stimulation. Resting and acute stress-induced changes in whole-body cortisol levels in vivo we...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1995.1122
更新日期：1995-09-01 00:00:00
abstract：:In many fishes, dopamine (DA) strongly inhibits luteinizing hormone (LH) release by direct action at the pituitary level. In this study, the effect of DA on LH synthesis was examined by detecting its β-subunit mRNA level in immature grass carp pituitary cells. Results showed that DA inhibited LHβ mRNA expression and i...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2011.04.024
更新日期：2011-08-01 00:00:00
abstract：:Organophosphorus pesticides are known to disturb glucose homeostasis and increase incidence of metabolic disorders and diabetes via insulin resistance. The current study investigates the influence of malathion on insulin signaling pathways and the protective effects of N-acetylcysteine (NAC). Malathion (200 mg/kg) and...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2014.10.002
更新日期：2015-05-01 00:00:00
abstract：:Three species of fish that are phylogenetically older than other members of the bony fish lineage were selected to determine if gonadotropin-releasing hormone (GnRH) is present in their brains. Brain extracts were prepared from each species and found to contain immunoreactive (ir) GnRH. To further characterize the mol...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(91)90063-c
更新日期：1991-10-01 00:00:00
abstract：:The rate-limiting and regulated step in steroidogenesis, the conversion of cholesterol to pregnenolone, is facilitated by the steroidogenic acute regulatory protein (StAR) and cytochrome P450 cholesterol side-chain cleavage (P450scc). We have isolated cDNAs encoding StAR and P450scc from the Atlantic stingray, Dasyati...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2010.04.018
更新日期：2010-08-01 00:00:00
abstract：:Primary cultured gill epithelia from goldfish and rainbow trout were used to investigate a role for cortisol in the regulation of paracellular permeability and tight junction (TJ) protein transcript abundance in representative stenohaline versus euryhaline freshwater (FW) fish gills. Glucocorticoid and mineralocortico...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2011.04.023
更新日期：2011-07-01 00:00:00
abstract：:Daily variations in circulating melatonin concentrations have been measured at monthly intervals from April to December 1986 in an Antarctic bird, the emperor penguin, Aptenodytes forsteri, maintained under natural conditions. Both duration of the elevated nighttime melatonin levels and amplitude of the day-night rhyt...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(91)90048-b
更新日期：1991-11-01 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：:A significant reduction in stress-induced plasma cortisol levels is apparent in mature male rainbow trout compared to immature fish of both sexes and of the same age and strain. Mean plasma cortisol levels in groups of immature fish subjected to a standard 1-hr confinement stress were consistently higher (range 93.9 +...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1995.1073
更新日期：1995-06-01 00:00:00
abstract：:Implantation of cortisol pellets in a dorsal lymph sac reduced the frequency with which toads replaced the strata cornea of the epidermis. Except in a few cases, however, the replaced strata cornea were not shed as in a normal moult. The mean interval between replacements of strata cornea rose from about 9-10 days in ...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(88)90291-2
更新日期：1988-07-01 00:00:00
abstract：:Uptake of L-thyroxine (T4) by isolated trout hepatocytes was characterized after 1-min incubation of cells in a Hanks' balanced salts medium containing glucose and [125I]T4. Centrifugation through silicone oil and glycine buffer (pH 10.5) was used to separate cells from the medium and minimize extracellular binding of...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1993.1057
更新日期：1993-04-01 00:00:00
