The IGFBP-3 Stimulation Test: A New Tool for the Diagnosis of Growth Hormone Deficiency in Children.
The IGFBP-3 Stimulation Test: A New Tool for the Diagnosis of Growth Hormone Deficiency in Children.
This project is designed to answer the question: Is there an acute IGFBP-3 response in normal
 children?

 Our specific hypothesis states that under the influence of growth hormone secretagogues,
 intact IGFBP-3 molecule will undergo proteolysis and liberate IGFBP-3 fragments, along with
 other components of the ternary complex. This proteolysis will result in measurable rise in
 IGFBP-3, which will indicate the subject's growth hormone status. Short children with growth
 hormone deficiency will not show an IGFBP-3 response.
The diagnosis of growth hormone deficiency is problematic, given the shortcoming of the
 standard growth hormone stimulation test. This study is designed to investigate a new tool
 for the diagnosis of growth hormone deficiency.

 Ten short, prepubertal children, who fulfill the inclusion criteria, will undergo a
 two-secretagogue standard growth hormone stimulation test, and an insulin like growth factor
 binding protein-3 (IGFBP-3) stimulation test simultaneously. During this test, components of
 the ternary complex moieties, viz, insulin-like growth factor-I (IGF-I), IGFBP-3 and acid
 labile subunit (ALS) will also be measured along with growth hormone.

 The aim of this study is to detect an acute rise in IGFBP-3 of >15% from baseline.

 The importance of this study is that it inculcates the specificity and improved sensitivity
 of stimulated IGFBP-3 in the diagnosis of growth hormone deficiency.
Inclusion Criteria:

 -  Bone age < 10 years female, < 12 years male

 -  Pubertal status: Girls: Tanner I for breast development. Boys: testicular volume of ≤
 3 cc, as measured by the standardized orchidometer (Prader type). The onset of pubic
 hair development up to and including Tanner III is allowed in the study.

 -  Adequate nutrition: body mass index ≥ 25th percentile for gender.

 Exclusion Criteria:

 -  Syndromic short stature

 -  Chronic illnesses.

 -  Other disorders, including osteo- or chondrodystrophies, and endocrine causes of short
 stature such as Cushing syndrome, and untreated hypothyroidism.