title: Role of thyroid hormone in the control of growth hormone gene expression.
abstract: Growth hormone (GH) gene expression was examined in male Wistar rats (200 g) subjected to different manipulations of thyroid status. Thyroidectomy followed by 10 days of treatment with 0.03% methimazole added to drinking water caused a marked decrease in GH mRNA levels estimated by Northern Blot analysis. T3 administration (100 micrograms/100 g body weight, ip, twice daily) to euthyroid rats for one week caused a substantial increase in GH mRNA levels. In another set of experiments, thyroidectomized methimazole-treated rats were killed at different times after a single T3 injection (100 micrograms/100 g body weight, ip). T3 induced a prompt response in GH gene expression by 15 min that reached a maximum after 1 h, remaining so up to 4 h. We conclude that in the rat, GH gene expression is highly dependent on thyroid hormones. Because of the rapidity of the response, the effect is probably mediated by a transcriptional mechanism.
authors.affiliation: Departamento de Fisiologia e Biofisica, Universidade de São Paulo, Brasil.
authors.forename: C B
authors.initials: CB
authors.lastname: Volpato
authors.forename: M T
authors.initials: MT
authors.lastname: Nunes
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D015870:Gene Expression; D013006:Growth Hormone / Q000235:genetics*; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013963:Thyroid Hormones / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors; D014158:Transcription, Genetic; D014285:Triiodothyronine, Reverse / Q000008:administration & dosage
chemical_list: D012333:RNA, Messenger; D013963:Thyroid Hormones; D014285:Triiodothyronine, Reverse; D013006:Growth Hormone