Serum Ghrelin Concentrations are Increased in Children With Growth Hormone Insensitivity and Decrease During Long-Term Insulinlike Growth Factor-I Treatment

2008 ◽  
Vol 56 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Aysin Uckun-Kitapci ◽  
Andrea M. Haqq ◽  
Jonathan Q. Purnell ◽  
Kenneth Newcomb ◽  
Hakan Gulkesen ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Normal Control ◽  
Blood Draw ◽  
Gh Secretion ◽  
Factor I ◽  
Insulinlike Growth Factor ◽  
Igf I ◽  
Growth Factor I ◽  
Insulinlike Growth Factor I

BackgroundGhrelin increases food intake, body weight, and growth hormone (GH) secretion. Serum concentrations of ghrelin are low in obese hyperinsulinemic persons, are reduced by infusion of insulin into normal-weight subjects, and are increased in underweight hypoinsulinemic patients with anorexia nervosa. Laron syndrome is an autosomal recessive disorder of GH insensitivity that results in decreased insulinlike growth factor-I (IGF-I) synthesis and growth failure. These patients have elevated GH levels, excess adipose tissue, and are insulin resistant. Because IGF-I has insulinlike actions and patients with GH insensitivity syndrome (GHIS) exhibit excess adiposity, we sought to determine whether ghrelin levels were elevated in these patients and potentially regulated by IGF-I replacement.MethodsThirteen children with GHIS and 20 normal control children matched for age, sex, and body mass index underwent complete physical examination and a fasting blood draw at baseline. The GHIS subjects then underwent follow-up fasting blood draws during therapy with human recombinant IGF-I (80-120 μg/kg, given subcutaneously twice daily). Fasting glucose, insulin, and IGF-I concentrations were measured at the time of collection. Fasting total ghrelin levels were measured on stored serum samples.ResultsThe GHIS subjects had 2-fold higher fasting ghrelin levels (2926 ± 1869 pg/mL) compared with the normal control children (1492 ± 493 pg/mL; P = 0.009), and mean ghrelin values were reduced 56% during 6.4 ± 0.2 years of IGF-I replacement (P < 0.05).ConclusionsGrowth hormone resistance and low IGF-I levels are associated with elevated ghrelin levels, which may potentiate GH secretion and adiposity in these children. Suppression of ghrelin during IGF-I treatment suggests a novel mechanism potentially regulating ghrelin levels.

scholarly journals Constitutive phosphorylation of the receptor for insulinlike growth factor I in cells transformed by the src oncogene.

1990 ◽  
Vol 10 (7) ◽  
pp. 3626-3634 ◽  
Author(s):  
L M Kozma ◽  
M J Weber
Keyword(s):  
Growth Factor ◽  
Beta Subunit ◽  
Transformed Cells ◽  
Receptor Phosphorylation ◽  
Factor I ◽  
Insulinlike Growth Factor ◽  
Igf I ◽  
Growth Factor I ◽  
Insulinlike Growth Factor I ◽  
In Cells

Many oncogene products have been shown to bear strong homology to or to interact with components of normal cellular signal transduction. We have previously shown that a glycoprotein band of 95 kilodaltons (kDa) becomes tyrosine phosphorylated in chick cells transformed by Rous sarcoma virus and that tyrosine phosphorylation of this protein band correlates tightly with phenotypic transformation in cells infected with a large and diverse panel of src mutants (L. M. Kozma, A. B. Reynolds, and M. J. Weber, Mol. Cell. Biol. 10:837-841, 1990). In this communication, we report that a component of the 95-kDa glycoprotein band is related or identical to the 95-kDa beta subunit of the receptor for insulinlike growth factor I (IGF-I). We found that the beta subunit of the IGF-I receptor comigrated on polyacrylamide gels with a component of the 95-kDa glycoprotein region from src-transformed cells under both reducing and nonreducing gel conditions and had a very similar partial phosphopeptide map. To further test the hypothesis that the beta subunit of the IGF-I receptor becomes tyrosine phosphorylated in cells transformed by pp60src, a human cell line that expressed the IGF-I receptor was transformed by src. Comparison of IGF-I receptors immunoprecipitated from normal and transformed cells revealed that the beta subunit of the IGF-I receptor became constitutively tyrosine phosphorylated in src-transformed cells. Moreover, IGF-I receptor phosphorylation induced by src was synergistic with that induced by the hormone: IGF-I-stimulated autophosphorylation of the receptor was much greater in src-transformed cells than in untransformed HOS cells even at maximal concentrations of IGF-I. This increased responsiveness to IGF-I was not due to increases in receptor number, time course of phosphorylation, or affinity for hormone. Finally, no IGF-I-like activity could be detected in culture supernatants collected from the src-transformed cells, suggesting that the increased receptor phosphorylation observed in the src-transformed cells may be mediated by an intracellular mechanism rather than an external autocrine stimulation. Our data demonstrate that the IGF-I receptor becomes constitutively tyrosine phosphorylated in src-transformed cells. This finding raises the possibility that pp60v-src alters growth regulation at least in part by phosphorylating and activating this growth factor receptor.

Effects of octreotide on insulin-like growth factor I and metabolic indices in growth hormone-treated growth hormone-deficient patients

1993 ◽  
Vol 129 (5) ◽  
pp. 399-408 ◽  
Author(s):  
Torben Laursen ◽  
Jens OL Jorgensen ◽  
Hans Ørskov ◽  
Jens Møller ◽  
Alan G Harris ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Animal Studies ◽  
Area Under The Curve ◽  
Insulin Like Growth Factor ◽  
Gh Secretion ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I ◽  
Igfbp 3

Animal studies have demonstrated that in addition to inhibiting growth hormone (GH) secretion octreotide inhibits in a direct manner hepatic or peripheral insulin-like growth factor I (IGF-I) generation. To test this hypothesis in humans we studied ten GH-deficient patients with frequent blood sampling during 38 h on two occasions. Regular GH therapy was discontinued 72 h prior to each study period. At the start of each study a subcutaneous (sc) injection of GH (3 IU/m2) was given (at 18.00 h). In a single-blinded crossover design, patients received a continuous sc infusion of either octerotide (200 μg/24 h) or placebo (saline). The pharmacokinetics of GH were similar on the two occasions. The area under the curve±sem of serum GH was 142.5±53.6 μg·l−1·h−1 (octreotide) and 144.8±41.8 μg·l−1·h−1 (placebo), (p=0.73); Cmax (μg/l) was 12.5±1.47 (octreotide) and 12.8±1.42 (placebo) (p=0.83), and Tmax (h) was 6.1±0.97 (octreotide) and 5.2±0.65 (placebo) (p=0.49). Growth hormone administration was associated with an increase in serum IGF-I (μg/l), which was identical during the two studies, from 85.3±19.4 to 174.25±30.3 for octreotide and from 97.0±26.4 to 158.8±28.2 for placebo. Mean IGF-I levels (μg/l) were 138.2±25.1 (octreotide) and 134.5±28.6 (placebo) (p=0.78). Similarly, the increase in IGF binding protein 3 (IGFBP-3) levels was identical. Mean IGFBP-3 levels (μg/l) were 2303±323 (octreotide) and 2200±361 (placebo) (p=0.25). Mean insulin levels were significantly lower during octreotide treatment (39.9±17.9 mU/l) than during placebo (59.7±17.8 mU/l) (p<0.05). Mean blood glucose levels were elevated significantly during octreotide infusion (5.98±0.23 mmol/l for octreotide and 5.07±0.16 mmol/l for placebo; p=0.001). Glucagon levels decreased non-significantly (p=0.07) and IGFBP-1 levels tended to increase during infusion of octreotide although not significantly (p=0.41). Levels of the lipid intermediates were identical on the two occasions. Alanine and lactate levels were significantly increased during octreotide infusion. Mean levels of blood alanine (μmol/l) were 470.8±24.2 (octreotide) and 360.1±17.8 (placebo) (p<0.02). Mean levels of blood lactate were 1038±81.0 (octreotide) and 894.4±73.8 (placebo) (p<0.04). We conclude that short-term continuous sc infusion of octreotide has no direct effect on the generation of IGF-I or the pharmacokinetics of exogenous GH in GH-deficient man.

Dental Development in Children with Growth Hormone Insensitivity Syndrome: Demirjian Analysis of Serial Panoramic Radiographs

2009 ◽  
Vol 46 (4) ◽  
pp. 409-414 ◽  
Author(s):  
Richard Campbell ◽  
Randy Weinshel ◽  
Philippe Backeljauw ◽  
Stephen Wilson ◽  
Judy Bean ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Tooth Development ◽  
Dental Development ◽  
Panoramic Radiographs ◽  
Factor I ◽  
Insulinlike Growth Factor ◽  
Growth Hormone Insensitivity ◽  
Growth Factor I ◽  
Insulinlike Growth Factor I

Objective: This study evaluates the effects of 8 years of insulinlike growth factor-I therapy on tooth development in patients with growth hormone insensitivity syndrome. Methods: Forty-nine panoramic radiographs were evaluated from eight patients (six boys, two girls). Seven teeth in the mandibular left region were graded according to the Demirjian system. Radiographs were taken at the start of insulinlike growth factor-I therapy and were continued at approximately yearly intervals for 8 years. Results: Three of six boys and one of two girls who began treatment with insulinlike growth factor-I at earlier ages experienced an increase in the rate of tooth development. One of six boys who began treatment with insulinlike growth factor-I at a later age had a slower rate of dental development. The patients had more rapid tooth maturation during the beginning of treatment. By the end of treatment, all patients had normal dental maturity for their age. Conclusions: Treatment of growth hormone insensitivity syndrome with insulinlike growth factor-I appears to lead to an increase in dental maturation, particularly in younger patients. After 8 years all patients had achieved normal dental development.

Somatomedin C/insulinlike growth factor I during liver regeneration in the rat

1985 ◽  
Vol 248 (5) ◽  
pp. E618-E623 ◽  
Author(s):  
W. E. Russell ◽  
A. J. D'Ercole ◽  
L. E. Underwood
Keyword(s):  
Growth Factor ◽  
Liver Regeneration ◽  
Mean Value ◽  
Hepatocellular Injury ◽  
Somatomedin C ◽  
Factor I ◽  
Insulinlike Growth Factor ◽  
Igf I ◽  
Growth Factor I ◽  
Insulinlike Growth Factor I

We measured immunoreactive somatomedin C/insulinlike growth factor I (Sm C/IGF I) in blood and tissues of rats following partial hepatectomy (PH) to determine a possible regulatory role for this growth factor in liver regeneration. From a mean value of 0.66 U/ml +/- 0.19 before PH, the serum Sm C/IGF I rose to 1.09 +/- 0.08 1 h after PH [P less than 0.001 vs. sham-hepatectomized (SH) values]. Concurrently there was a twofold rise in serum aspartate aminotransferase, suggesting that the rise in Sm C/IGF I may be the result of hepatocellular injury rather than a specific secretory event. In the subsequent 22 h, serum Sm C/IGF I of PH rats fell to 0.31 +/- 0.06 U/ml, compared with 0.73 +/- 0.03 in SH rats. During this time, liver concentrations of the peptide declined to 30% of basal, whereas lung and kidney fell to only approximately 60% of basal. As the Sm C/IGF I declined, hepatic DNA synthesis increased 10-fold in PH animals. Our results, therefore, do not support a mitogenic role for Sm C/IGF I in the regulation of liver regulation. Food consumption was markedly depressed in the 22 h after PH (20.8 +/- 2.6 vs. 4.33 +/- 2.9 g/day; P less than 0.001). PH and pair-fed SH rats had serum Sm C/IGF I concentrations that were indistinguishable (0.31 +/- 0.06 vs. 0.35 +/- 0.11 U/ml), although liver tissue concentrations were lower in PH rats (0.04 +/- 0.01 U/g vs. 0.07 +/- 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

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