Distribution of insulin-like growth factor-I receptor mRNA in rat brain. Regulation in the hypothalamo-neurohypophysial system.
The distribution and regulation of mRNA for the IGF-I receptor (IGF-I-R) in the adult rat brain were studied by in-situ hybridization with a 35S-labelled cRNA probe. The pituitary gland showed a strong hybridization signal in the pars tuberalis (the surface of the median eminence), pars distalis and pars intermedia. Within the brain, a strong hybridization signal was found in the circumventricular organs, olfactory bulb, hippocampus, cerebellum and hypothalamus. IGF-I-R mRNA was consistently found in cell bodies of the hypothalamo-neurohypophysial system. Six days of intermittent salt-loading resulted in an increase in IGF-I-R gene expression in the supraoptic nucleus. The increase in IGF-I-R mRNA was accompanied by a high expression of c-Fos immunoreactivity in the same cells. The presence and regulation of IGF-I-R mRNA in the hypothalamus suggest that IGF-I may affect the local plasticity or modulation of activated magnocellular neurones by an autocrine or paracrine action through specific receptors in the hypothalamo-neurohypophysial system.
Aguado
F
F
Instituto Cajal, CSIC, Madrid, Spain.
Rodrigo
J
J
Cacicedo
L
L
Mellström
B
B
D000818:Animals; D001923:Brain Chemistry; D003681:Dehydration / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis / Q000235:genetics; D015347:RNA Probes; D018075:RNA, Complementary; D051381:Rats; D017208:Rats, Wistar; D017526:Receptor, IGF Type 1 / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics
D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D015347:RNA Probes; D018075:RNA, Complementary; D017526:Receptor, IGF Type 1