1. T3 acutely increases GH mRNA translation rate and GH secretion in hypothyroid rats
- Author
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F. Goulart da Silva, Augusto Ducati Luchessi, Maria Tereza Nunes, Gisele Giannocco, and Rui Curi
- Subjects
Male ,medicine.medical_specialty ,Somatotropic cell ,Biology ,Biochemistry ,Peptide Elongation Factor 1 ,Endocrinology ,Hypothyroidism ,Internal medicine ,Polysome ,medicine ,Protein biosynthesis ,Animals ,Secretion ,RNA, Messenger ,Insulin-Like Growth Factor I ,Rats, Wistar ,Cytoskeleton ,Molecular Biology ,Messenger RNA ,Body Weight ,Translation (biology) ,Organ Size ,Actins ,Growth hormone secretion ,Rats ,Gene Expression Regulation ,Liver ,Growth Hormone ,Pituitary Gland ,Polyribosomes ,Protein Biosynthesis ,Triiodothyronine ,Protein Binding - Abstract
Cytoskeleton controls the stability of transcripts, by mechanisms that involve mRNAs and eEF1A attachment to it. Besides, it plays a key role in protein synthesis and secretion, which seems to be impaired in somatotrophs of hypothyroid rats, whose cytoskeleton is disarranged. This study investigated the: eEF1A and GH mRNA binding to cytoskeleton plus GH mRNA translation rate and GH secretion, in sham-operated and thyroidectomized rats treated with T3 or saline, and killed 30 min thereafter. Thyroidectomy reduced: (a) pituitary F-actin content, and eEF1A plus GH mRNA binding to it; (b) GH mRNA recruitment to polysome; and (c) liver IGF-I mRNA expression, indicating that GH mRNA stability and translation rate, as well as GH secretion were impaired. T3 acutely reversed all these changes, which points toward a nongenomic action of T3 on cytoskeleton rearrangement, which might contribute to the increase on GH mRNA translation rate and GH secretion.
- Published
- 2010
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