Effects of the IGF-I/IGFBP-3 complex on GH and ghrelin nocturnal concentrations in low birth weight children.
OBJECTIVE
There is limited information regarding the effects of IGF-I and/or IGFBP-3 on circulating ghrelin concentrations. To determine the effects of IGF-I on GH and ghrelin concentrations, we examined the GH and ghrelin nocturnal profiles before and after the administration of the IGF-I/-IGFBP-3 complex (Iplex) to low birth weight children.


METHODS
The children were studied on two separate occasions, the first under basal conditions, and the second time after the sc administration of 1 mg/kg of Iplex at 2100 h. Blood samples for determination of GH and ghrelin were obtained every 20 min between 2300 h and 0700 h, while the children were sleeping. In each patient, we calculated the mean GH and ghrelin area under the curve (GH AUC and GHR AUC), both under basal conditions and after the administration of the IGF-I/IGFBP-3 complex.


METHODS
The study was performed at a University Research Centre located at a General Hospital in Santiago, Chile.


METHODS
Twenty prepubertal children (11 boys and 9 girls), born after a full-term pregnancy with a birth weight below 2.8 kg were studied at a mean +/- SEM age of 7.3 +/- 0.5 years (range 4-11 years). Their mean height was -1.8 +/- 0.3 standard deviation score (SDS) and their mean BMI was 0.1 +/- 0.2 SDS at the time of the study.


RESULTS
Mean nocturnal GH AUC exhibited a significant decrease (2903 +/- 185 vs 1860 +/- 122 ng/ml min, P < 0.01), whereas mean GHR AUC showed a significant increase after administration of the IGF-I/IGFBP-3 complex (68 +/- 16 vs 288 +/- 36 ng/ml min, P < 0.01).


CONCLUSIONS
These findings indicate that the IGF-I/IGFBP-3 complex appears to have opposite effects on circulating GH and ghrelin concentrations in low birth weight children, suggesting that, in addition to its known negative feed-back effect on GH, IGF-I and/or IGFBP-3 may have a positive feed-back effect on ghrelin.
Iñiguez
German
G
Institute of Maternal and Child Research, University of Chile, Santiago, Chile.
Salazar
Teresa
T
Roman
Rossana
R
Avila
Alejandra
A
Gunn
Ronald D
RD
Cassorla
Fernando
F
D019540:Area Under Curve; D002648:Child; D005500:Follow-Up Studies; D054439:Ghrelin; D006130:Growth Disorders / Q000378:metabolism*; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007230:Infant, Low Birth Weight / Q000378:metabolism*; D007231:Infant, Newborn; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000494:pharmacology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D046912:Multiprotein Complexes / Q000494:pharmacology*; D036361:Peptide Hormones / Q000097:blood*; D012636:Secretory Rate; D018709:Statistics, Nonparametric
D054439:Ghrelin; D018972:Insulin-Like Growth Factor Binding Protein 3; D046912:Multiprotein Complexes; D036361:Peptide Hormones; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone