Dietary Protein Restriction Decreases Insulin-Like Growth Factor I Independent of Insulin and Liver Growth Hormone Binding*

Endocrinology ◽  
1989 ◽  
Vol 124 (5) ◽  
pp. 2604-2611 ◽  
Author(s):  
D. MAITER ◽  
T. FLIESEN ◽  
L. E. UNDERWOOD ◽  
M. MAES ◽  
G. GERARD ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Dietary Protein ◽  
Protein Restriction ◽  
Insulin Like Growth Factor ◽  
Hormone Binding ◽  
Liver Growth ◽  
Dietary Protein Restriction ◽  
Factor I ◽  
Growth Factor I

Evidence That Pretranslational and Translational Defects Decrease Serum Insulin-Like Growth Factor-I Concentrations during Dietary Protein Restriction*

Endocrinology ◽  
1991 ◽  
Vol 129 (1) ◽  
pp. 429-435 ◽  
Author(s):  
JEAN-PAUL THISSEN ◽  
SANDRINE TRIEST ◽  
BILLIE M. MOATS-STAATS ◽  
LOUIS E. UNDERWOOD ◽  
TEKLA MAUERHOFF ◽  
...  
Keyword(s):  
Growth Factor ◽  
Dietary Protein ◽  
Serum Insulin ◽  
Protein Restriction ◽  
Insulin Like Growth Factor ◽  
Dietary Protein Restriction ◽  
Factor I ◽  
Growth Factor I

Translational status of the insulin-like growth factor-I mRNAs in liver of protein-restricted rats

1992 ◽  
Vol 132 (1) ◽  
pp. 141-147 ◽  
Author(s):  
J.-P. Thissen ◽  
L. E. Underwood
Keyword(s):  
Growth Factor ◽  
Dietary Protein ◽  
Mrna Translation ◽  
Protein Restriction ◽  
Insulin Like Growth Factor ◽  
Dietary Protein Restriction ◽  
Factor I ◽  
Mrna Transcripts ◽  
Igf I ◽  
Growth Factor I

ABSTRACT Dietary protein restriction in young rats decreases serum insulin-like growth factor-I (IGF-I) concentrations and the amount of liver IGF-I mRNA, suggesting that regulation for the liver IGF-I gene expression in this model occurs at a pretranslational level. To determine whether there is also translational control, we assessed the association of the liver IGF-I mRNA transcripts with polysomes in livers of normally fed (15% dietary protein) versus protein-restricted (5% dietary protein) rats. One week of dietary protein restriction reduces serum IGF-I concentrations by 54% and the amount of liver IGF-I mRNA by 35%, with the 7·5 kb size-class of IGF-I mRNA being the most affected (−48%). Protein restriction reduces the amount of the polysomal IGF-I mRNAs by 30%, a value in close agreement with the changes in total IGF-I mRNAs. Protein restriction is not associated with changes in the distribution of IGF-I mRNAs between the polysomal and non-polysomal fractions. All major size-classes of IGF-I mRNA transcripts (7·5, 4·7, 1·7, 0·9–1·2 kb) are associated with the polysomes in both dietary groups, suggesting involvement in the initiation phase of the IGF-I translation. We conclude that no untranslatable pool of IGF-I mRNAs is present in the liver of protein-restricted animals. Protein restriction, however, decreases slightly the mean size of polysomes. This decrease in ribosomal number associated with the IGF-I mRNA could decrease translational efficiency. Our data suggest that dietary protein restriction does not impair the initiation of IGF-I mRNA translation. Journal of Endocrinology (1992) 132, 141–147

scholarly journals Reduction of Serum Insulin-like Growth Factor-I by Dietary Protein Restriction Is Age Dependent

1989 ◽  
Vol 26 (5) ◽  
pp. 415-419 ◽  
Author(s):  
Therese Fliesen ◽  
Dominique Maiter ◽  
Guy Gerard ◽  
Louis E Underwood ◽  
Marc Maes ◽  
...  
Keyword(s):  
Growth Factor ◽  
Dietary Protein ◽  
Serum Insulin ◽  
Protein Restriction ◽  
Insulin Like Growth Factor ◽  
Dietary Protein Restriction ◽  
Factor I ◽  
Age Dependent ◽  
Growth Factor I

Divergent Responses of Serum Insulin-Like Growth Factor-I and Liver Growth Hormone (GH) Receptors to Exogenous GH in Protein-Restricted Rats*

Endocrinology ◽  
1990 ◽  
Vol 126 (2) ◽  
pp. 908-913 ◽  
Author(s):  
J. P. THISSEN ◽  
S. TRIEST ◽  
L. E. UNDERWOOD ◽  
M. MAES ◽  
J. M. KETELSLEGERS
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Serum Insulin ◽  
Insulin Like Growth Factor ◽  
Liver Growth ◽  
Factor I ◽  
Growth Factor I ◽  
Gh Receptors

Influence of circulating insulin-like growth factor-I compared with that of intrarenal insulin-like growth factor-I on proximal nephron receptor density in rats

1992 ◽  
Vol 83 (2) ◽  
pp. 233-239 ◽  
Author(s):  
Michael K. Hise ◽  
Quintina Corteza ◽  
David K. Klassen ◽  
John H. Sadler
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Dietary Protein ◽  
Dominant Role ◽  
Scatchard Analysis ◽  
Insulin Like Growth Factor ◽  
Receptor Density ◽  
Factor I ◽  
Growth Factor I ◽  
Circulating Levels

1. We examined the effects of dietary protein manipulations in partially nephrectomized (one and one-third nephrectomy) and normal rats to gain perspective on the relative importance of circulating versus intrarenal (collecting tubule) insulin-like growth factor-I in the control of proximal nephron receptor density. In addition, we studied the factors that influence liver insulin-like growth factor-I secretion in partially nephrectomized rats. 2. Dietary protein restriction (6% versus 40%) lowered circulating levels of insulin and insulin-like growth factor-I in both normal and partially nephrectomized rats up to 3 weeks after institution of the diets; however, growth hormone levels were little changed. Reduced renal mass stimulated intrarenal production of insulin-like growth factor I regardless of the diet. 3. Scatchard analysis revealed that the density of insulin-like growth factor-I receptors on glomerular and proximal tubule basolateral membranes increased when circulating levels of insulin-like growth factor-I were diminished, despite raised levels of intrarenal insulin-like growth factor-I, in partially nephrectomized rats. 4. Circulating insulin-like growth factor-I, rather than the tissue level, plays the dominant role in the control of proximal nephron receptor density under physiological conditions. Insulin, but not growth hormone, may play a role in liver insulin-like growth factor-I secretion in partially nephrectomized rats during dietary manipulations.

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