Thyroxine elicits divergent changes in mRNA levels for two urea cycle enzymes and one gluconeogenic enzyme in tadpole liver

Morris, Sidney M.

doi:10.1016/0003-9861(87)90479-6

Cited by 32 publications

(15 citation statements)

References 40 publications

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“…Since others have shown that TH up-regulates the transcription of the CPS gene in R. catesbeiana liver [Morris, 1987;Galton et al, 19911, we theorized that this hormone might also affect a change in the abun-4OTC same gel shown in A, demonstrates the enhanced synthesis of a 38 kDa protein in the liver of TH-treated tadpoles. Western immunoblot analysis (Im) using a rat anti-OTC antibody [Shore et al, 19831 identifies the 38 kDa protein as OTC.…”

Section: Isolation and Characterization Of Cdnas Encoding The R Catementioning

confidence: 84%

“…Since others have shown that TH up-regulates the transcription of the CPS gene in R. catesbeiana liver [Morris, 1987;Galton et al, 19911, we theorized that this hormone might also affect a change in the abun- dance of the mRNAs encoding tadpole liver OTC, the second enzyme in the urea cycle, and that any change should precede the enhanced synthesis andlor accumulation of OTC in the tadpole liver. In order to address this possibility, we isolated a cDNA sequence encoding a R. catesbeiana OTC.…”

Section: Isolation and Characterization Of Cdnas Encoding The R Catementioning

confidence: 98%

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Sequential up‐regulation of thyroid hormone β receptor, ornithine transcarbamylase, and carbamyl phosphate synthetase mRNAs in the liver of Rana catesbeiana tadpoles during spontaneous and thyroid hormone‐induced metamorphosis

1992

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During both spontaneous and thyroid hormone (TH)-induced metamorphosis, the Rana catesbeiana tadpole undergoes postembryonic developmental changes in its liver which are necessary for its transition from an ammonotelic larva to a ureotelic adult. Although this transition ultimately results from marked increases in the activities and/or de novo synthesis of the urea cycle enzymes, the precise molecular means by which TH exerts this tissue-specific response are presently unknown. Recent reports, using RNA from whole Xenopus laevis tadpole homogenates and indirect means of measuring TH receptor (TR) mRNAs, suggest a correlation between the up-regulation of TR beta-mRNAs and the general morphological changes occurring during amphibian metamorphosis. To assess whether or not this same relationship exists in a TH-responsive tissue, such as liver, we isolated and characterized a cDNA clone containing the complete nucleotide sequence for a R. catesbeiana urea cycle enzyme, ornithine transcarbamylase (OTC), as well as a genomic clone containing a portion of the hormone-binding domain of a R. catesbeiana TR beta gene. Through use of these homologous sequences and a heterologous cDNA fragment encoding rat carbamyl phosphate synthetase (CPS), we directly determined the relative levels of the TR beta, OTC, and CPS mRNAs in liver from spontaneous and TH-induced tadpoles. Our results establish that TH affects an up-regulation of mRNAs for its own receptor prior to up-regulating CPS and OTC mRNAs. Moreover, results with cultured tadpole liver demonstrate that TH, in the absence of any other hormonal influence, can affect an up-regulation of both the TR beta and OTC mRNAs.

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Section: Isolation and Characterization Of Cdnas Encoding The R Catementioning

confidence: 84%

“…Since others have shown that TH up-regulates the transcription of the CPS gene in R. catesbeiana liver [Morris, 1987;Galton et al, 19911, we theorized that this hormone might also affect a change in the abun- dance of the mRNAs encoding tadpole liver OTC, the second enzyme in the urea cycle, and that any change should precede the enhanced synthesis andlor accumulation of OTC in the tadpole liver. In order to address this possibility, we isolated a cDNA sequence encoding a R. catesbeiana OTC.…”

Section: Isolation and Characterization Of Cdnas Encoding The R Catementioning

confidence: 98%

Sequential up‐regulation of thyroid hormone β receptor, ornithine transcarbamylase, and carbamyl phosphate synthetase mRNAs in the liver of Rana catesbeiana tadpoles during spontaneous and thyroid hormone‐induced metamorphosis

1992

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“…Previous analysis of thyroid hormone action has identified a number of structural genes that show altered expression when the hormone is present. For example, malic enzyme mRNA increases in rat liver and heart (Dozin et al, 1986), and transcription of two enzymes of the urea cycle and one gluconeogenic enzyme increases in tadpole liver (Morris, 1987) in response to thyroid hormone. Synthesis of mRNA for both subunits of thyrotropin (TSH), the pituitary glycoprotein that regulates thyroid hormone secretion, decreases in response to thyroid hormone (Shupnik, Chin, Habener, and Ridgway, 1985).…”

Section: Thyroid-hormone-regulated Genesmentioning

confidence: 99%

Metamorphosis of the amphibian eye

Hoskins

1990

J. Neurobiol.

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For many metamorphosing amphibians, the visual system must remain functional as the animal changes from an aquatic to a terrestrial habitat. Thyroid hormone, the trigger for metamorphosis, brings about changes at all levels of the animal, and profoundly alters the visual system, from cellular changes within the eye to new central connections subserving the binocular vision that develops during metamorphosis in some species. I will survey the alterations in the visual system in the metamorphosis of several Amphibian groups, and consider the role of thyroid hormone in bringing about these transformations through action at the molecular level.

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“…Prior to use, the hormones were diluted into the tadpole's water at a final concentration of 26 nM for T4 and 1-5 nM for T s (Morris 1987), with daily changes of the solutions. Control tadpoles were treated identically except that an equal volume of 4 rnM NaOH without hormone was added.…”

Section: Treatment Of X Laevis Tadpolesmentioning

confidence: 99%

Developmental and thyroid hormone-dependent regulation of pancreatic genes in Xenopus laevis.

Shi

Brown²

1990

Genes Dev.

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We have isolated and sequenced a cDNA encoding Xenopus laevis pancreatic trypsin, which has -70% amino acid sequence identity to mammalian trypsinogen. Northern blotting analysis shows that the trypsin gene is activated just before the tadpole starts to feed, reaches peak activity in the swimming tadpole (premetamorphosis), and is then repressed during prometamorphosis, attaining its lowest activity at the climax of metamorphosis. The same gene is then activated again in frogs but to a much lower level. The pattern of the changes in trypsin gene expression is followed by at least two other pancreas-specific genes and marks the remodeling of the pancreas of the animal at metamorphosis. Thyroid hormone, which is the causative agent of metamorphosis, can down-regulate trypsin gene expression prematurely.

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Thyroxine elicits divergent changes in mRNA levels for two urea cycle enzymes and one gluconeogenic enzyme in tadpole liver

Cited by 32 publications

References 40 publications

Sequential up‐regulation of thyroid hormone β receptor, ornithine transcarbamylase, and carbamyl phosphate synthetase mRNAs in the liver of Rana catesbeiana tadpoles during spontaneous and thyroid hormone‐induced metamorphosis

Sequential up‐regulation of thyroid hormone β receptor, ornithine transcarbamylase, and carbamyl phosphate synthetase mRNAs in the liver of Rana catesbeiana tadpoles during spontaneous and thyroid hormone‐induced metamorphosis

Metamorphosis of the amphibian eye

Developmental and thyroid hormone-dependent regulation of pancreatic genes in Xenopus laevis.

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