scholarly journals Effects of Melatonin on Peripheral Reproductive Function: Regulation of Testicular GnIH and Testosterone

Endocrinology ◽  
2011 ◽  
Vol 152 (9) ◽  
pp. 3461-3470 ◽  
Author(s):  
Nicolette L. McGuire ◽  
Kristina Kangas ◽  
George E. Bentley
Keyword(s):  
Expression Patterns ◽  
Reproductive Function ◽  
Melatonin Receptors ◽  
Sex Steroid ◽  
European Starlings ◽  
Steroid Secretion ◽  
Local Inhibition ◽  
Gonadotropin Inhibitory Hormone ◽  
The Brain

Study of seasonal reproduction has focused on the brain. Here, we show that the inhibition of sex steroid secretion can be seasonally mediated at the level of the gonad. We investigate the direct effects of melatonin on sex steroid secretion and gonadal neuropeptide expression in European starlings (Sturnus vulgaris). PCR reveals starling gonads express mRNA for gonadotropin inhibitory hormone (GnIH) and its receptor (GnIHR) and melatonin receptors 1B (Mel 1B) and 1C (Mel 1C). We demonstrate that the gonadal GnIH system is regulated seasonally, possibly via a mechanism involving melatonin. GnIH/ GnIHR expression in the testes is relatively low during breeding compared with outside the breeding season. The expression patterns of Mel 1B and Mel 1C are correlated with this expression, and melatonin up-regulates the expression of GnIH mRNA in starling gonads before breeding. In vitro, GnIH and melatonin significantly decrease testosterone secretion from LH/FSH-stimulated testes before, but not during, breeding. Thus local inhibition of sex steroid secretion appears to be regulated seasonally at the level of the gonad, by a mechanism involving melatonin and the gonadal GnIH system.

scholarly journals The Murine Neuronal Receptor NgR1 Is Dispensable for Reovirus Pathogenesis

2021 ◽  
Author(s):  
Pavithra Aravamudhan ◽  
Camila Guzman-Cardozo ◽  
Kelly Urbanek ◽  
Olivia Welsh ◽  
Jennifer Konopka-Anstadt ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Target Cells ◽  
Viral Attachment ◽  
Genetic Ablation ◽  
Murine Homolog ◽  
Intramuscular Inoculation ◽  
Neural Tissues ◽  
Mammalian Orthoreovirus ◽  
The Brain

Engagement of host receptors is essential for viruses to enter target cells and initiate infection. Expression patterns of receptors in turn dictate host and tissue tropism and disease pathogenesis during infection. Mammalian orthoreovirus (reovirus) displays serotype-dependent patterns of tropism in the murine central nervous system (CNS) that are dictated by viral attachment protein σ1. However, the receptor that mediates reovirus CNS tropism is unknown. Two proteinaceous receptors have been identified for reovirus, junctional adhesion molecule-A (JAM-A) and Nogo 66 receptor 1 (NgR1). Engagement of JAM-A is required for reovirus hematogenous dissemination but is dispensable for neural spread. To determine whether NgR1 functions in reovirus neuropathogenesis, we compared virus replication and disease following inoculation of wild-type (WT) and NgR1-/- mice. Genetic ablation of NgR1 did not alter replication of neurotropic reovirus strain T3SA- in the intestine and transmission to the brain following peroral inoculation. Viral titers in neural tissues following intramuscular inoculation, which provides access to neural dissemination routes, also were comparable in WT and NgR1-/- mice, suggesting that NgR1 is dispensable for reovirus neural spread to the CNS. The absence of both NgR1 and JAM-A also did not alter replication, neural tropism, and virulence of T3SA- following direct intracranial inoculation. In agreement with these findings, we found that the human but not the murine homolog of NgR1 functions as a receptor and confers efficient reovirus binding and infection of nonsusceptible cells in vitro. These results eliminate functions for JAM-A and NgR1 in shaping CNS tropism in mice and suggest that other receptors, yet to be identified, support this function.

scholarly journals Peripheral clocks and their role in circadian timing: insights from insects

2001 ◽  
Vol 356 (1415) ◽  
pp. 1791-1799 ◽  
Author(s):  
Jadwiga M. Giebultowicz
Keyword(s):  
Feedback Loop ◽  
Clock Genes ◽  
Expression Patterns ◽  
Isolated Organs ◽  
Peripheral Organs ◽  
Peripheral Clocks ◽  
Molecular Components ◽  
The Brain

Impressive advances have been made recently in our understanding of the molecular basis of the cell–autonomous circadian feedback loop; however, much less is known about the overall organization of the circadian systems. How many clocks tick in a multicellular animal, such as an insect, and what are their roles and the relationships between them? Most attempts to locate clock–containing tissues were based on the analysis of behavioural rhythms and identified brain–located timing centres in a variety of animals. Characterization of several essential clock genes and analysis of their expression patterns revealed that molecular components of the clock are active not only in the brain, but also in many peripheral organs of Drosophila and other insects as well as in vertebrates. Subsequent experiments have shown that isolated peripheral organs can maintain self–sustained and light sensitive cycling of clock genes in vitro . This, together with earlier demonstrations that physiological output rhythms persist in isolated organs and tissues, provide strong evidence for the existence of functionally autonomous local circadian clocks in insects and other animals. Circadian systems in complex animals may include many peripheral clocks with tissue–specific functions and a varying degree of autonomy, which seems to be correlated with their sensitivity to external entraining signals.

METABOLISM OF TESTOSTERONE IN THE ANTERIOR PITUITARY GLAND AND THE CENTRAL NERVOUS SYSTEM OF THE EUROPEAN STARLING (STURNUS VULGARIS)

1977 ◽  
Vol 75 (3) ◽  
pp. 347-354 ◽  
Author(s):  
R. MASSA ◽  
L. CRESTI ◽  
L. MARTINI
Keyword(s):  
Central Nervous System ◽  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Sturnus Vulgaris ◽  
European Starling ◽  
European Starlings ◽  
The Central Nervous System ◽  
The Brain

The metabolism of testosterone was studied in vitro in anterior pituitary, hypothalamic and hyperstriatal tissues taken from male European starlings in the autumn. In all the tissues studied, testosterone was converted into 5α-androstan-17β-ol-3-one (5α-DHT), 5β-androstan-17β-ol-3-one (5β-DHT), 5β-androstane-3α,17β-diol (5β-THT), 5β-androstane-3,-17-dione and androst-4-ene-3,17-dione. The 5α-DHT was produced in significantly greater amounts by the pituitary gland than by the hypothalamus and hyperstriatum. The amount of 5α-DHT produced, however, was very low in comparison with the amounts of 5β-reduced metabolites. The amount of 5β-reductase was also higher in the pituitary gland than in the two nervous tissues. The ratios between the production of 5β-DHT, 5β-THT and 5β-androstane-3,17-dione were, however, different in the three tissues: 5β-DHT was produced in the greatest quantities by the hyperstriatum, while the production of 5β-THT, 5β-androstane-3,17-dione and androst-4-ene-3,17-dione was greatest in pituitary tissue. The role of 5α- and 5β-reduced metabolites in the pituitary gland and in the brain of birds is unknown, but some possibilities arising from the present results are discussed.

scholarly journals Divergent expression patterns of pituitary gonadotropin subunit and GnRH receptor genes to continuous GnRH in vitro and in vivo

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marija M. Janjic ◽  
Rafael M. Prévide ◽  
Patrick A. Fletcher ◽  
Arthur Sherman ◽  
Kosara Smiljanic ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Expression Patterns ◽  
Reproductive Function ◽  
Gnrh Receptor ◽  
Continuous Treatment ◽  
Pituitary Cells ◽  
Cell Content ◽  
Major Factors

AbstractContinuous, as opposed to pulsatile, delivery of hypothalamic gonadotropin-releasing hormone (GnRH) leads to a marked decrease in secretion of pituitary gonadotropins LH and FSH and impairment of reproductive function. Here we studied the expression profile of gonadotropin subunit and GnRH receptor genes in rat pituitary in vitro and in vivo to clarify their expression profiles in the absence and continuous presence of GnRH. Culturing of pituitary cells in GnRH-free conditions downregulated Fshb, Cga, and Gnrhr expression, whereas continuous treatment with GnRH agonists upregulated Cga expression progressively and Gnrhr and Fshb expression transiently, accompanied by a prolonged blockade of Fshb but not Gnrhr expression. In contrast, Lhb expression was relatively insensitive to loss of endogenous GnRH and continuous treatment with GnRH, probably reflecting the status of Egr1 and Nr5a1 expression. Similar patterns of responses were observed in vivo after administration of a GnRH agonist. However, continuous treatment with GnRH stimulated LH secretion in vitro and in vivo, leading to decrease in LH cell content despite high basal Lhb expression. These data suggest that blockade of Fshb expression and depletion of the LH secretory pool are two major factors accounting for weakening of the gonadotroph secretory function during continuous GnRH treatment.

scholarly journals Implication of Tryptophan 2,3-Dioxygenase and its Novel Variants in the Hippocampus and Cerebellum during the Developing and Adult Brain

2010 ◽  
Vol 3 ◽  
pp. IJTR.S4372 ◽  
Author(s):  
Masaaki Kanai ◽  
Hiroshi Funakoshi ◽  
Toshikazu Nakamura
Keyword(s):  
Real Time ◽  
Expression Patterns ◽  
Adult Brain ◽  
Tryptophan Metabolism ◽  
Rt Pcr ◽  
Early Postnatal Development ◽  
Novel Variants ◽  
Full Form ◽  
The Brain

Tryptophan 2,3-dioxygenase (TDO) is a first and rate-limiting enzyme for the kynurenine pathway of tryptophan metabolism. Using Tdo−/− mice, we have recently shown that TDO plays a pivotal role in systemic tryptophan metabolism and brain serotonin synthesis as well as emotional status and adult neurogenesis. However, the expression of TDO in the brain has not yet been well characterized, in contrast to its predominant expression in the liver. To further examine the possible role of local TDO in the brain, we quantified the levels of tdo mRNA in various nervous tissues, using Northern blot and quantitative real-time RT-PCR. Higher levels of tdo mRNA expression were detected in the cerebellum and hippocampus. We also identified two novel variants of the tdo gene, termed tdo variant1 and variant2, in the brain. Similar to the known TDO form (TDO full-form), tetramer formation and enzymatic activity were obtained when these variant forms were expressed in vitro. While quantitative real-time RT-PCR revealed that the tissue distribution of these variants was similar to that of tdo full-form, the expression patterns of these variants during early postnatal development in the hippocampus and cerebellum differed. Our findings indicate that in addition to hepatic TDO, TDO and its variants in the brain might function in the developing and adult nervous system. Given the previously reported associations of tdo gene polymorphisms in the patients with autism and Tourette syndrome, the expression of TDO in the brain suggests the possible influence of TDO on psychiatric status. Potential functions of TDOs in the cerebellum, hippocampus and cerebral cortex under physiological and pathological conditions are discussed.

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

Identification of Differentially Expressed Genes Using cDNA-AFLP During Six Days In Vitro Tuberization of Potato

Zuriat ◽  
2015 ◽  
Vol 14 (1) ◽  
Author(s):  
Nono Carsono ◽  
Christian Bachem
Keyword(s):  
Gene Expression ◽  
Developmental Process ◽  
Expression Patterns ◽  
Induction Medium ◽  
In Vitro Tuberization ◽  
Storage Organ ◽  
Developmentally Regulated ◽  
Study Gene Expression ◽  
Differential Pattern

Tuberization in potato is a complex developmental process resulting in the differentiation of stolon into the storage organ, tuber. During tuberization, change in gene expression has been known to occur. To study gene expression during tuberization over the time, in vitro tuberization system provides a suitable tool, due to its synchronous in tuber formation. An early six days axillary bud growing on tuber induction medium is a crucial development since a large number of genes change in their expression patterns during this period. In order to identify, isolate and sequencing the genes which displaying differential pattern between tuberizing and non-tuberizing potato explants during six days in vitro tuberization, cDNA-AFLP fingerprint, method for the visualization of gene expression using cDNA as template which is amplified to generate an RNA-fingerprinting, was used in this experiment. Seventeen primer combinations were chosen based on their expression profile from cDNA-AFLP fingerprint. Forty five TDFs (transcript derived fragment), which displayed differential expressions, were obtained. Tuberizing explants had much more TDFs, which developmentally regulated, than those from non tuberizing explants. Seven TDFs were isolated, cloned and then sequenced. One TDF did not find similarity in the current databases. The nucleotide sequence of TDF F showed best similarity to invertase ezymes from the databases. The homology of six TDFs with known sequences is discussed in this paper.

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