Molecular mechanisms of regulation of growth hormone gene expression in cultured rat pituitary cells by thyroid and glucocorticoid hormones
In cultured GC cells, a rat pituitary tumor cell line, growth hormone (GH) is induced in a synergistic fashion by physiologic concentrations of thyroid and glucocorticoid hormones. Abundant evidence indicates that these hormones mediate this response via their specific receptors. The purpose of this thesis is to explore the mechanisms by which these hormones affect GH production. When poly (A){sup +} RNA was isolated from cells grown both with and without hormones and translated in a cell-free wheat germ system, the preGH translation products were shown to be proportional to immunoassayable GH production under all combinations of hormonal milieux, indicating that changes in GH production is modulated at a pretranslational level. A cDNA library was constructed from poly (A){sup +}RNA and one clone containing GH cDNA sequences was isolated. This was used to confirm the above results by Northern dot blot analysis. This probe was also used to assess hormonal effects on GH mRNA half-life and synthetic rates as well as GH gene transcription rates in isolated nuclei. Using a pulse-chase protocol in which cellular RNA was labeled in vivo with ({sup 3}H)uridine, and quantitating ({sup 3}H)GHmRNA directly by hybridization to GH cDNA bound to nitrocellulose filters, GHmRNA was found to have a half-life of approximately 50 hours, and was not significantly altered by the presence of inducing hormones.
- Research Organization:
- New York Univ., NY (USA)
- OSTI ID:
- 6172599
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GLUCOCORTICOIDS
BIOCHEMICAL REACTION KINETICS
STH
BIOSYNTHESIS
THYROID HORMONES
CELL CULTURES
DNA
GENE REGULATION
PITUITARY GLAND
RATS
RECEPTORS
RNA
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TUMOR CELLS
URIDINE
ADRENAL HORMONES
ANIMAL CELLS
ANIMALS
AZINES
BODY
CORTICOSTEROIDS
ENDOCRINE GLANDS
GLANDS
HETEROCYCLIC COMPOUNDS
HORMONES
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KETONES
KINETICS
MAMMALS
MEMBRANE PROTEINS
NUCLEIC ACIDS
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PEPTIDE HORMONES
PITUITARY HORMONES
PREGNANES
PROTEINS
PYRIMIDINES
REACTION KINETICS
RIBOSIDES
RODENTS
STEROIDS
SYNTHESIS
URACILS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques