Regulation of renal growth and IGFBP-4 expression by triiodothyronine during rat development.
The insulin-like growth factors (IGFs) and insulin-like growth factor binding proteins (IGFBPs), which regulate IGF activity, play a fundamental role in renal cell proliferation and differentiation. The thyroid hormone is considered to be required for kidney development; excess induces local hypertrophy and hyperplasia. The aim of the present study was to investigate the possible involvement of the IGF/IGFBP system in thyroid hormone-induced renal growth during the development of the rat. Our results show that thyroid hormone withdrawal by 6-propyl-2-thiouracil (PTU)-treatment of rats at all ages had no effect on renal IGFBP-4 mRNA levels, whereas the abundance of the serum protein was decreased compared to controls. Intraperitoneal triiodothyronine (T3) administration to hypothyroid rats resulted in renal hypertrophy associated with a significant upregulation of IGFBP-4 expression with increased levels of renal IGFBP-4 mRNA and serum protein. T3-induced upregulation of IGFBP-4 expression suggests the involvement of the local IGF/IGFBP system in T3-induced renal hypertrophy.
Voci
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Dipartimento di Biologia Sperimentale, Ambientale ed Applicata, Università di Genova, Italy. vocia@unige.it
Demori
Bottazzi
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C
Fugassa
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D000818:Animals; D015152:Blotting, Northern; D001835:Body Weight / Q000187:drug effects; D007037:Hypothyroidism / Q000139:chemically induced / Q000473:pathology; D018974:Insulin-Like Growth Factor Binding Protein 4 / Q000096:biosynthesis* / Q000235:genetics; D007668:Kidney / Q000033:anatomy & histology / Q000254:growth & development*; D008024:Ligands; D008297:Male; D009929:Organ Size / Q000187:drug effects; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects*
D018974:Insulin-Like Growth Factor Binding Protein 4; D008024:Ligands; D012333:RNA, Messenger; D014284:Triiodothyronine; D013974:Thyroxine