Abstract：
:In the summer of 1991 (late May to early September), I measured seasonal levels of plasma androgens in two species of plethodontid salamanders to assess the temporal relationship of elevated plasma androgen levels with spermatogenic events and with sexual behavior. In both species, spermatogenesis occurs in the spring and summer. In one species, Plethodon jordani, mating occurs in the fall. In the other species, Desmognathus ochrophaeus, the mating season is prolonged, occurring both in the fall and in the spring. In P. jordani, plasma testosterone (T) levels were lowest in June and highest in late August, such that elevated plasma T levels coincided with the development of secondary sexual characteristics and the time when mating behavior occurs. Plasma dihydrotestosterone (DHT) levels for P. jordani were lowest in June and rose significantly in mid July when spermiation began. In D. ochrophaeus, plasma T and DHT levels were lowest during June and July and highest in late August. Elevated T and DHT levels coincided with spermiation and with the period when mating behavior occurs. Data for these two salamander species indicate that maximally elevated plasma androgens were temporally dissociated from the peak of spermatogenesis; maximal androgen levels were more closely associated with spermiation and the development of secondary sexual characteristics.
journal_name
Gen Comp Endocrinoljournal_title
General and comparative endocrinologyauthors
Woodley SKdoi
10.1006/gcen.1994.1175subject
Has Abstractpub_date
1994-11-01 00:00:00pages
206-14issue
2eissn
0016-6480issn
1095-6840pii
S0016-6480(84)71175-0journal_volume
96pub_type
杂志文章abstract：:An investigation into vitamin D-like molecules has been performed on whole extracts of the terrestrial amphipod Orchestia cavimana, using a sensitive nonequilibrium assay employing 1,25-(OH)2 D receptor from calf thymus. Relatively large amounts of these secosteroid-like molecules were observed and they varied in conc...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(91)90070-m
更新日期：1991-10-01 00:00:00
abstract：:In goldfish, two endogenous gonadotropin-releasing hormones (GnRH), salmon GnRH (sGnRH) and chicken GnRH-II (cGnRH-II), are thought to stimulate growth hormone (GH) release via protein kinase C (PKC) and subsequent increases in intracellular Ca(2+) levels ([Ca(2+)](i)). In contrast, the signaling mechanism for seroton...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2008.07.021
更新日期：2008-10-01 00:00:00
abstract：:Hagfish, Myxine glutinosa, were used in a series of experiments to determine a possible role for calcitonin in plasma and urine electrolyte balance. Individual animals were anaesthetised and implanted with polythene cannulae for monitoring blood pressure and for infusion/injection. Urine was collected by manual palpat...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(88)90297-3
更新日期：1988-07-01 00:00:00
abstract：:In this study, parathyroid hormone (PTH) receptor binding was examined in the membrane fraction of the endometrium of the shell gland of laying and nonlaying hens by the use of (125)I-PTH-related peptide (PTHrP) binding assays. Specific (125)I-PTHrP binding was found in the endometrium of the shell gland and increased...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1999.7395
更新日期：2000-02-01 00:00:00
abstract：:The cell types within the endocrine pancreatic tissue and anterior intestine of larvae and juveniles of representatives of the two southern-hemisphere families (Mordaciidae and Geotriidae) were compared, using immunohistochemistry and antisera against insulin (lamprey, bovine), two somatostatins (SST-14, -34), two PP-...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1993.1152
更新日期：1993-11-01 00:00:00
abstract：:Undifferentiated spermatogonia (Aund) or spermatogonial stem cells (SSCs) are committed to the establishment and maintenance of spermatogenesis and fertility throughout a male's life and are located in a highly specialized microenvironment called niche that regulates their fate. Although several studies have been deve...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2018.06.019
更新日期：2019-03-01 00:00:00
abstract：:Insulin and IGF-I binding has been studied in brown trout (Salmo trutta) wheat germ agglutinin semipurified receptors from embryos (organogenesis), larvae (yolk sac), juveniles (2.98 +/- 0.21 g bw) and adults (111.6 +/- 6.92 and 522 +/- 53 g bw). Embryos and larvae were sampled at 5 and 12 weeks after fertilization (D...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.2001.7621
更新日期：2001-05-01 00:00:00
abstract：:Genetic sex determination leads to gonadal differentiation and ultimately the differences between the sexes in steroid hormone secretion. Gonadal steroidogenesis is critical for the development of a sexually dimorphic phenotype and adult reproductive function. Control of gonadal development and steroidogenesis is unde...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/s0016-6480(02)00019-9
更新日期：2002-06-01 00:00:00
abstract：:Recent studies have revealed nesfatin-1 as a hypothalamic neuropeptide, regulating food intake, energy expenditure and reproduction primarily by acting on the hypothalamic-pituitary-gonadal axis. Nesfatin-1 is also localized in several peripheral tissues including testes. However, functional significance of nesfatin-1...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2018.10.022
更新日期：2019-01-15 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：:The functional abilities of 9.5-, 10.5-, 11.5-, and 12.5-day-old chick embryos to respond to exogenous thyrotrophin-releasing hormone (TRH) were evaluated by means of changes in plasma total thyroxine (T4). T4 concentrations were determined 3.0, 6.0, 12.0, and 24.0 hr after TRH treatment. The data of the present inves...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/0016-6480(84)90112-6
更新日期：1984-08-01 00:00:00
abstract：:Elasmobranchs (sharks, skates, and rays) are a primarily carnivorous group of fish, consuming few carbohydrates. Further, they tend to exhibit delayed responses to glucose and insulin administration in vivo relative to mammals, leading to a presumption of glucose-intolerance. To investigate the glucoregulatory capabil...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2017.01.016
更新日期：2017-06-01 00:00:00
abstract：:Juvenile hormone (JH) regulation of the synthesis of LHPI, the major secretory protein of the long hyaline tubule in the male accessory reproductive gland (MARG) of Melanoplus sanguinipes, was examined by in vitro radiolabeling and immunoprecipitation. In MARG taken from normal insects JH III immediately stimulates pr...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1995.1046
更新日期：1995-04-01 00:00:00
abstract：:Measurement of fish steroids in water provides a non-invasive alternative to measurement in blood samples, offering the following advantages: zero or minimal intervention (i.e. no anaesthetic, bleeding or handling stress); results not being biased by sampling stress; repeat measurements on the same fish; the possibili...
journal_title：General and comparative endocrinology
pub_type： 杂志文章,评审
doi：10.1016/j.ygcen.2006.11.006
更新日期：2007-08-01 00:00:00
abstract：:Urinary excretion of the thyroid hormones (TH) L-thyroxine (T4), and 3,5,3'-triiodo-L-thyronine (T3) and their derivatives was studied in urinary-catheterized rainbow trout (mean wt. 227 g) fasted for 2 days under a 12-hr L:12-hr D photocycle in running water (12 degrees). Catheterized trout were intracardiac-injected...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1994.1128
更新日期：1994-08-01 00:00:00
abstract：:The steroid hormone 5α-dihydrotestosterone (DHT) is one of the most physiologically important androgens in male vertebrates, with the exception of teleost fish, in which it is generally assumed that DHT does not play any major physiological role. However, this assumption is challenged by the fact that all the componen...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2013.06.017
更新日期：2013-09-15 00:00:00
abstract：:The concentrations of norepinephrine in hypothalamus and norepinephrine and epinephrine in head kidney were significantly decreased in treated tilapia (Oreochromis aureus) during the time course of cold exposure (12 degrees) as compared to the control (25 degrees). The elevation of norepinephrine and epinephrine in pl...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.2001.7772
更新日期：2002-03-01 00:00:00
abstract：:Application of alpha-MSH immunohistochemistry to the brain of elasmobranchs (Scyliorhinus torazame and Etmopterus brachyurus) demonstrated a marked species difference concerning the distribution of the alpha-MSH-like molecule in the brain. In S. torazame, alpha-MSH-like immunoreactive cells were present in the hypotha...
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：:Glucose-induced insulin secretion from pancreatic beta-cells involves metabolism-induced membrane depolarization and voltage-dependent Ca(2+) influx. The electrical events in beta-cell glucose sensing have been studied intensely using mouse islets of Langerhans, but data from other species, including models of type 2 ...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2008.12.017
更新日期：2009-04-01 00:00:00
abstract：:Neonatal handling of captive vertebrates can shape the development of their hypothalamo-pituitary-adrenal (HPA) axis and alter their ability to respond to stressful stimuli later in life. However, the long-term effects of such handling on this endocrine axis in free-living species are not well understood. We investiga...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2013.03.004
更新日期：2013-06-01 00:00:00
abstract：:Anthropogenic emissions of carbon dioxide in the atmosphere have generated rapid variations in atmospheric composition which drives major climate changes. Climate change related effects include changes in physico-chemical proprieties of sea and freshwater, such as variations in water temperature, salinity, pH/pCO2 and...
journal_title：General and comparative endocrinology
pub_type： 杂志文章,评审
doi：10.1016/j.ygcen.2020.113439
更新日期：2020-05-15 00:00:00
abstract：:The kisspeptin system is now accepted as a key regulator of vertebrate reproductive function, particularly the onset of puberty. In teleosts, the stimulatory effect of exogenous kisspeptins has been demonstrated mainly at the hypothalamic and pituitary levels of the reproductive axis, with very limited information per...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2013.06.005
更新日期：2013-09-15 00:00:00
abstract：:We studied the hepatic in vitro deconjugation and deiodination of glucuronide (G) and sulfate (S) conjugates of the thyroid hormones (TH) thyroxine (T(4)), 3,5,3'-triiodothyronine (T(3)), and 3,3', 5'-triiodothyronine (rT(3)) in trout. These conversions have not been studied in nonmammals. Deconjugation of T(4)G, T(3)...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1999.7326
更新日期：1999-09-01 00:00:00
abstract：:Orexin A (OXA), a hypothalamic neuropeptide, and its receptor (OX1R) are primarily expressed in lateral hypothalamus and are involved in the control of various biological functions. Expressions of OXA and OX1R have also been reported in peripheral organs like gastrointestinal and genital tracts. In the present study, ...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2015.11.005
更新日期：2016-12-01 00:00:00
abstract：:Cytosol and crude nuclear extracts of brains from female Diploptera punctata were found to contain a juvenile hormone-binding protein. The binding kinetics of the cytosol and nuclear juvenile hormone-binding proteins toward racemic [3H]JH III were determined using the dextran-coated charcoal assay. Both proteins show ...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1006/gcen.1994.1055
更新日期：1994-04-01 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：:Steroid hormone assessment using non-invasive sample collection techniques can reveal the reproductive status of aquatic mammals and the physiological mechanisms by which they respond to changes in their environment. A portion of the eastern North Pacific blue whale (Balaenoptera musculus) population that seasonally v...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2018.02.015
更新日期：2018-05-15 00:00:00
abstract：:Cytochrome P450 17A1 (P450c17) is the key enzyme required for the production of androgenic sex steroids by converting progestogens to androgens. 5α-reductases are enzymes that convert testosterone (T) to dihydrotestosterone (DHT), which has a greater affinity for androgen receptors (AR) and stronger action than T. Our...
journal_title：General and comparative endocrinology
pub_type： 杂志文章
doi：10.1016/j.ygcen.2017.09.015
更新日期：2017-12-01 00:00:00
abstract：:Fish egg quality can be defined as the ability of the egg to be fertilized and subsequently develop into a normal embryo. Similarly, sperm quality can be defined as its ability to successfully fertilize an egg and subsequently allow the development of a normal embryo. In the wild or under aquaculture conditions, the q...
journal_title：General and comparative endocrinology
pub_type： 杂志文章,评审
doi：10.1016/j.ygcen.2009.02.011
更新日期：2010-02-01 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
