Studies of gene expression in liver of insulin-like growth factor (IGF)-I, IGF binding protein-3 and growth hormone (GH) receptor/GH binding protein in rats treated neonatally with monosodium glutamate.
We studied the gene expression of the insulin-like growth factor (IGF)-I, IGF binding protein (IGFBP)-3 and growth hormone (GH) receptor (GHR)/GH binding protein (GHBP) in liver of rats treated neonatally with monosodium glutamate (MSG). The MSG-treated rats showed severe growth retardation and obesity compared to saline-injected controls. Serum IGF-I levels in MSG-treated rats were significantly lower than in the controls after 6 weeks of age (p < 0.01). IGF-I gene expression increased with age and was significantly lower in MSG-treated rats than in the controls (p < 0.01). IGFBP-3 gene expression was unaffected by age in both MSG-treated male rats and the controls, but was less in MSG-treated female rats than in their controls between 6 to 8 weeks of age. In our study of GHR/GHBP gene expression, MSG-treated rats of both sexes displayed a distinct 1.5 kbase band encoding GHBP RNA. We speculated that these changes reflect disruption of GH secretion in in vivo experimental models. Thus, MSG-treated rats are useful as in vivo models for study of the effect of GH disruption on developmental gene expression.
Kubota
A
A
Department of Paediatrics, Hamamatsu University School of Medicine, Japan.
Nakagawa
Y
Y
Igarashi
Y
Y
D000818:Animals; D000831:Animals, Newborn; D015152:Blotting, Northern; D001835:Body Weight; D002352:Carrier Proteins / Q000235:genetics*; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000235:genetics* / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011986:Receptors, Somatotropin / Q000235:genetics*; D012970:Sodium Glutamate / Q000494:pharmacology*
D002352:Carrier Proteins; D018969:Insulin-Like Growth Factor Binding Proteins; D012333:RNA, Messenger; D011986:Receptors, Somatotropin; D007334:Insulin-Like Growth Factor I; C051815:somatotropin-binding protein; D012970:Sodium Glutamate