Abstract:
:The effects of thyroid hormone on the production of vitamin A(2) retinoids from vitamin A(1) precursor were investigated in retinal pigmented epithelial (RPE) cells obtained from juvenile coho salmon. Specifically, changes in the production of both the storage and the free forms of radiolabeled 3,4-didehydroretinoids were measured after 24 and 48 h incubation with [11,12-(3)H]all-trans-retinol with (or in the absence of) exogenous 3,4,3'-triiodo-l-thyronine (T(3)). RPE cells incubated with radiolabeled all-trans-retinol showed double the production of radiolabeled 3,4-didehydroretinoids (both storage and free forms) after 48 h compared to 24 h incubation. The addition of T(3) had no significant effect on the production of didehydroretinyl esters (storage form) after 24 h incubation, but did have a significant effect after 48 h, with a ca. 50% reduction in the amount of labeled didehydroretinyl produced compared to the amount produced by the controls after 48 h. Essentially the same observation was made for the production of radiolabeled didehydroretinol (free form) where, after 48 h of incubation with T(3), there was a ca. 50% reduction in the amount of labeled didehydroretinol produced compared to the amount produced by the controls after 48 h. The reduction in both the storage and the free forms of didehydroretinoids indicates that T(3) probably had the effect of altering the activity of the "terminal ring dehydrogenase" enzyme which acts on the outer ring of retinoids. The scope of this experiment, however, does not indicate whether the production of didehydroretinoids is specific to the free or to the storage forms as retinoids within the RPE can shuttle between both forms. The results of this experiment do indicate that the in vitro observations of this experiment may be extended to in vivo and field observations. In vitro, T(3) by itself altered the production of didehydro-derivatives of retinoids. The changes in visual pigment complement seen in salmonids, which are due to changes in relative proportions of 11-cis-retinal and 11-cis-3,4-didehydroretinal in the photoreceptors, may also be the result of T(3) acting by itself on the RPE cells.
journal_name
Gen Comp Endocrinoljournal_title
General and comparative endocrinologyauthors
Alexander G,Sweeting R,McKeown BAdoi
10.1006/gcen.2001.7667keywords:
subject
Has Abstractpub_date
2001-08-01 00:00:00pages
192-202issue
2eissn
0016-6480issn
1095-6840pii
S0016-6480(01)97667-1journal_volume
123pub_type
杂志文章abstract::Perchlorate, an environmental contaminant, disrupts normal functioning of the thyroid. We previously showed that perchlorate disrupts behavior and gonad development, and induces external morphological changes in a vertebrate model organism, the threespine stickleback. Whether perchlorate alters these phenotypes via a ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2014.10.015
更新日期:2015-01-01 00:00:00
abstract::Pheromones are known to trigger either short-term behavioral responses, usually referred to as "releaser effects", or more long-term physiological changes, known as "primer effects", which especially affect reproductive function at the level of the gonadotrope axis. The precise mechanisms through which pheromones inte...
journal_title:General and comparative endocrinology
pub_type: 杂志文章,评审
doi:10.1016/j.ygcen.2013.03.008
更新日期:2013-07-01 00:00:00
abstract::Comparative hormone studies can reveal how physiology underlies life history variation. Here, we examined seasonal variation in plasma testosterone concentration between populations of male orange-crowned warblers (Vermivora celata) breeding in Fairbanks, Alaska (V. c. celata) and on Santa Catalina Island, California ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2010.04.019
更新日期:2010-09-15 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::Fasting animals must ration stored reserves appropriately for metabolic demands. Animals that experience fasting concomitant with other metabolically demanding activities are presented with conflicting demands of energy conservation and expenditure. Our objective was to understand how fasting northern elephant seals r...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2015.09.024
更新日期:2016-01-01 00:00:00
abstract::High levels of the amino acid neurotransmitter glutamate were found in the goldfish hypothalamus and pituitary using high performance liquid chromatography with fluorometric detection. A specific polyclonal antibody to glutamate was generated in the rabbit for immunocytochemistry. Localization studies demonstrated tha...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1996.0103
更新日期:1996-08-01 00:00:00
abstract::In vitro studies with liver homogenates of brook charr (Salvelinus fontinalis) demonstrate that the conversion of thyroxine (T4) to triiodothyronine (T3) is dependent upon temperature, pH, substrate, and homogenate concentration, supporting the hypothesis of an enzymatic hepatic T4 to T3 conversion. Dithiothreitol has...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(88)90151-7
更新日期:1988-05-01 00:00:00
abstract::The occurrence of myoendocrine-like cells investing the ampullar draining region of Malpighian tubules and neighboring midgut and hindgut regions of the ant Formica polyctena is reported. These striated muscle cells show small electron-dense endocrine-like granules (130 +/- 0.95 nm) in addition to myofilaments and ord...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1994.1110
更新日期:1994-07-01 00:00:00
abstract::Maternally derived yolk steroids have been found to elicit both short-term and long-term effects on offspring phenotype. Paradoxically, their effects can be strikingly specific given the often substantial concentrations present at oviposition, and they do not appear to uniformly affect all steroid-sensitive processes....
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2009.01.018
更新日期:2009-04-01 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::Living for extended periods in Antarctica exposes base personnel to extremes of daylength (photoperiod) and temperature. At the British Antarctic Survey base of Halley, 75°S, the sun does not rise for 110 d in the winter and does not set for 100 d in summer. Photoperiod is the major time cue governing the timing of se...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2017.05.010
更新日期:2018-03-01 00:00:00
abstract::Our previous study demonstrated that recombinant goldfish activin B stimulated goldfish FSHbeta but inhibited LHbeta expression. Similar to activin B, activin A also exhibited the inverse effects on the expression of the two gonadotropins. The novel dual effects of activins on FSH and LH in the goldfish raise an inter...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2003.08.012
更新日期:2004-01-01 00:00:00
abstract::We investigated post-natal development of the adrenocortical stress-response system in captive American kestrels (Falco sparverius) by measurements of baseline and stress-induced levels of corticosterone at ages 10, 16, 22, and 28 days post-hatching. Baseline levels of corticosterone increased significantly during pos...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/s0016-6480(02)00587-7
更新日期:2003-02-01 00:00:00
abstract::Serotonin (5-HT) is well known for modulating the release of GnRH and gonadotropin in teleosts. Reports on increased female:male ratio after the blockade of 5-HT biosynthesis proposed a role for 5-HT in brain sex differentiation. Two types of tryptophan hydroxylase (Tph), rate-limiting enzyme in the biosynthesis of 5-...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2009.11.009
更新日期:2010-04-01 00:00:00
abstract::Extrapituitary expression of the growth hormone (GH) gene has been reported for the immune system of various vertebrates. In the rainbow trout (Oncorhynchus mykiss), GH mRNA could be detected in several lymphoid organs and leucocytes by reverse transcriptase-polymerase chain reaction (RT-PCR). To understand the contro...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2005.01.008
更新日期:2005-05-15 00:00:00
abstract::The presence of multiple forms of gonadotropin-releasing hormone (GnRH) within a single brain is common among vertebrate species. In previous studies of reptiles, two forms of GnRH were isolated from the brain of alligators and the primary structure was determined to be that of chicken (c)GnRH-I and cGnRH-II. GnRH has...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1997.6970
更新日期:1997-11-01 00:00:00
abstract::The gonadotropins (GTHs) follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are the key regulators of reproduction. We determined the competence of heterologous recombinant GTHs at eliciting steroid secretion from carp ovaries at different reproductive stages. We collected carp ovaries at: early, mid and ...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2012.04.002
更新日期:2012-08-01 00:00:00
abstract::The potential effects of growth hormone (GH), prolactin (Prl), and triiodothyronine (T3) on gill Na+,K+-ATPase activity and corticosteroid receptor (CR) concentration (Bmax) and dissociation constant (Kd) were examined in juvenile Atlantic salmon (Salmo salar). Compared to controls, fish injected with GH (ovine, 5.0 m...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1006/gcen.1998.7172
更新日期:1998-11-01 00:00:00
abstract::In many mammal species, androgen levels in males are elevated during periods of mating activity, often to facilitate aggressive behavior between males over access to fertile females. However, this pattern might be less obvious in species with a rather low male-male aggression rate, or in those that are not strictly se...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2017.09.028
更新日期:2018-01-01 00:00:00
abstract::In evolutionary endocrinology, there is a growing interest in the extent and basis of individual variation in endocrine traits, especially circulating concentrations of hormones. This is important because if targeted by selection, such individual differences present the opportunity for an evolutionary response to sele...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2014.08.014
更新日期:2014-11-01 00:00:00
abstract::We demonstrated the presence of specific binding sites for bullfrog luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in a testicular crude plasma membrane fraction of the bullfrog, Rana catesbeiana. The equilibrium analysis of the binding showed that a straight line was fitted to the Scatchard plot of L...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(86)90207-8
更新日期:1986-02-01 00:00:00
abstract::Effects of adrenal corticosteroids on reproductive and endocrine functions of the gonads are well known, but reciprocal effects of gonadal hormones on the hypothalamo-pituitary-adrenal (HPA) axis and on adrenocortical steroidogenesis in particular have received much less attention. We investigated effects of gonadecto...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2008.07.018
更新日期:2008-09-01 00:00:00
abstract::We evaluated the effect of corticotropin-releasing hormone (CRH) on spatial distribution and downstream movement in an artificial stream in juvenile Chinook salmon (Oncorhynchus tshawytscha) during the period when the fish were able to tolerate seawater. An intracerebroventricular (ICV) injection of CRH (500 ng) to ha...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2004.02.004
更新日期:2004-05-15 00:00:00
abstract::Five neuropeptide genes are classified in the FMRF-related (FaRP) group: the Fmrf, dromyosuppressin (Dms), drosulfakinin (Dsk), neuropeptide F (npf) and short neuropeptide F (sNPF) genes coding for 8, 1, 2, 1 and 4 peptides, respectively. In order to compare their effects on the locomotor activity of Drosophila adults...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2013.05.023
更新日期:2013-09-15 00:00:00
abstract::The role of stress in the decline of Steller sea lions has become of interest in the identification of factors leading to their drastic decline and subsequent failure to recover. Serum cortisol was validated as a potential indicator of stress in three sub-populations inhabiting the majority of the Steller sea lions ra...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2009.06.006
更新日期:2010-01-01 00:00:00
abstract::Growth hormone (GH) is a key factor controlling postnatal growth and development. Despite growth-promoting effects in mammals, GH is not associated with muscle growth in the chicken. Janus kinase 2 (JAK2) has been identified as the first intracellular step in GH receptor (GHR) signaling in many species, however, there...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2005.05.001
更新日期:2005-11-01 00:00:00
abstract::A detailed study was made of sex differentiation in three anteroposteriorly distributed body regions of the long gonadal fold in young Pacific hagfish (Eptatretus stouti) from 12.4 to 45 cm in length. In general, the posterior region, adjacent to the cloaca, remained undifferentiated, and only in specimens more than 2...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(90)90315-d
更新日期:1990-02-01 00:00:00
abstract::Circadian rhythm is well known to play a pivotal role in reproduction but the presence of a gonadal circadian rhythm is opening a lot of questions about a local regulation of reproduction. In the present study, we first set to identify the key genes driving circadian rhythmicity from the gonadal transcriptome of the s...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2020.113707
更新日期:2020-12-30 00:00:00
abstract::Four genomes and two transcriptomes from six Chelicerate species were analyzed for the presence of neuropeptide and neurohormone precursors and their GPCRs. The genome from the spider Stegodyphus mimosarum yielded 87 neuropeptide precursors and 101 neuropeptide GPCRs. High neuropeptide transcripts were also found in t...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/j.ygcen.2015.07.014
更新日期:2016-11-09 00:00:00
abstract::Circannual and circadian variations in plasma levels of steroids were estimated by radioimmunoassay in the female and male catfish, Heteropneustes fossilis, over two consecutive annual reproductive cycles. In the female catfish, testosterone (T), estradiol-17 beta (E2), and estrone (E1) were detectable in the plasma o...
journal_title:General and comparative endocrinology
pub_type: 杂志文章
doi:10.1016/0016-6480(83)90221-6
更新日期:1983-05-01 00:00:00