title: T3 acutely increases GH mRNA translation rate and GH secretion in hypothyroid rats.
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 30min 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.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1524, 05508-900, São Paulo, SP, Brazil.
authors.forename: F Goulart da
authors.initials: FG
authors.lastname: Silva
authors.forename: G
authors.initials: G
authors.lastname: Giannocco
authors.forename: A D
authors.initials: AD
authors.lastname: Luchessi
authors.forename: R
authors.initials: R
authors.lastname: Curi
authors.forename: M T
authors.initials: MT
authors.lastname: Nunes
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D013006:Growth Hormone / Q000235:genetics* / Q000378:metabolism*; D007037:Hypothyroidism / Q000235:genetics* / Q000473:pathology; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D009929:Organ Size / Q000187:drug effects; D020648:Peptide Elongation Factor 1 / Q000378:metabolism; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D011132:Polyribosomes / Q000187:drug effects / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D014176:Protein Biosynthesis / Q000187:drug effects*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D000199:Actins; D020648:Peptide Elongation Factor 1; D012333:RNA, Messenger; D014284:Triiodothyronine; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone