Histochemical localization of IGF-I and IGF-II mRNA in the rat between birth and adulthood.
We describe the postnatal ontogeny and localization of insulin-like growth factors I and II (IGF-I and -II) in the rat. We have used oligodeoxyribonucleotide probes for in situ hybridization (hybridization histochemistry) and for Northern blotting. IGF-II mRNA is strongly expressed in liver, skeletal muscle, perichondrium, leptomeninges and choroid plexus of the newborn. Demonstrable levels fall dramatically in the liver at 18-20 days postnatally but persist for longer periods in muscle and remain undiminished throughout life in the pia/choroid plexus, indicating that different control mechanisms operate in these tissues. IGF-I mRNA is predominantly found in the liver. Its level in this organ rises well before levels of IGF-II fall. This suggests that distinct factors govern the expression of IGF-I and -II genes.
Beck
F
F
Department of Anatomy, University of Leicester, UK.
Samani
N J
NJ
Byrne
S
S
Morgan
K
K
Gebhard
R
R
Brammar
W J
WJ
D000818:Animals; D001345:Autoradiography; D015152:Blotting, Northern; D001923:Brain Chemistry; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D008099:Liver / Q000032:analysis* / Q000254:growth & development; D024510:Muscle Development; D009132:Muscles / Q000032:analysis*; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D013002:Somatomedins / Q000235:genetics*
D012333:RNA, Messenger; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II