Insulin-like Growth Factor-Binding Protein-3 (IGFBP-3)

Insulin-like-growth-factor-binding-protein-3 (IGFBP-3) binds insulin-like-growth-factor (IGF-1) circulating in the blood. In this process, the action of IGF-1 is regulated by IGFBP-3. IGF-1 (somatomedin C) is one of the differentiation and growth factors.

The synthesis of IGFBP-3 takes place STH-dependently in the liver. Serum IGFBP-3 levels indicate the release of growth hormone over several days:

  • Serum IGFBP-3 level has a better correlation with growth hormone secretion.
  • Because of its higher concentrations compared with IGF-1, it seems to be particularly advantageous in the diagnosis of childhood growth disorders.
  • In addition, the test can also be used to monitor STH substitution therapy (growth hormone therapy).

The procedure

Material needed

  • Blood serum, frozen

Preparation of the patient

  • Not necessary

Disruptive factors

  • Not known

Standard values

Age Normal values
2-23 months of age (LM) 0.7-2.5 μg/ml
2nd-4th year of life (LY). 0.9-3.8 μg/ml
6-10 LJ 1.3-4.7 μg/ml
11.16. LJ 1.8-6.1 μg/ml
20-25 LJ 1.5-5.5 μg/ml
35TH-50TH L YR 1.5-3.6 μg/ml
> 55. LJ 1.3-2.6 μg/ml

Indications

  • Diagnosis and differential diagnosis of growth disorders, especially infantile short stature and acromegaly.
  • Somatopause – progressive reduction in STH secretion over the adult life span. This culminates in a nadir and consistently lowered serum STH levels (IGF-1 ↓; IGFBP-3 ↓) from around age 50.
  • STH substitution therapy (e.g., due toshort stature; somatopause).

Interpretation

Interpretation of increased values

  • Acromegaly – endocrinologic disorder caused by overproduction of the growth hormone somatotropin (STH), with marked enlargement of the body’s end limbs or protruding parts of the body (acras), such as the hands, feet, lower jaw, chin, nose, and eyebrow ridges.

Interpretation of depressed values

  • Decreased values
  • Somatopause
  • Too decreased IGFBP-3 lead to:
    • Chronic malnutrition
    • Diabetes mellitus
    • Fasting
    • Liver damage

Further notes

  • IGFBP-3 is a superior parameter in suspected growth disorders; monitoring of STH substitution therapy.