Growth metabolism

Product name

IGFBP-1

Insulin like Growth Factor Binding Protein-1

Cat-Nr.E01
Range0.1 - 128 ng/ml (after dilution 1:16)
Sensitivity0.02 ng/ml
Incubation time2 hours RT
Sample volume20 ┬Ál (after dilution 1:16 for serum and plasma)
Sample type

Serum, plasma (EDTA and Heparin), urine and other human body fluids, cell culture supernatants. Results in citrate plasma are about 15% reduced.

Sample preparation

Samples have to be chilled as soon as possible after collection. Long-term storage should be carried out at –20°C or below. Maximum 3 freeze/thaw cycles.

Reference values

Serum of healthy adults

   Bereich (ng/ml) median (ng/ml) 
Female (n=33) 0.23 – 16.07 4.24
Male (n=36) 0.42 – 17.94 2.71

 

Species

Human

Tests96 Tests
MethodELISA
Intended use

The Insulin-like Growth Factors I and –II are free in body fluids and tissues but are bound to specific binding proteins. Until today seven different binding proteins (IGFBP-1 to -7) can be differentiated, additionally several IGFBP-related proteins have also been detected. Bioavailability of IGF is regulated by these IGFBPs as well as their proteolytic fragments can also exert IGF-independent effects, like influencing cell migration or proliferation.

IGFBP-1 (Placental Protein 12) consists of 234 aminoacids and has a molecular weight of approximately 25 kDa. The coding DNA region is located on chromosome 7. IGFBP-1 is mainly synthesized by foetal and adult liver tissue and decidual endometrium. Intensity of expression varies enduring menstruation with a maximal expression in the late secretory phase. Further IGFBP-1 expression seems to be regulated by Insulin concentration, with Insulin inhibiting the expression. Insulin regulation results in diurnal fluctuations of up to factor 10.

In pregnancy IGFBP-1 maternal serum concentration increases significantly with maximal values in the second trimester or 22.-23. week of gestation (75,8 ng/ml) and decreases slowly until term. IGFBP-1 concentration are not only increased in maternal but also in foetal serum and with extremely high concentrations in amnion fluid. Here concentration can reach more than the 1000-fold of serum values.
Short term IGFBP-1 serum concentration is strongly influenced by nutrition level and therewith by insulin. Decreasing IGFBP-1 levels can be found enduring fasting or in diabetes; IGFBP-1 levels increase in case of intensive exercises.
Thoroughly investigated was the diagnostic value in insulin resistance and pre-term rupture of the membrane and specially in the second field a significant diagnostic value could be demonstrated.

-Energy metabolism
Based on the influence of Insulin on IGFBP-1 serum concentrations IGFBP-1 is said to be a possible marker for insulin resistance. Because measurement of IGFBP-1 is much easier facilitated than Glucose-uptake rate this would simplify diagnosis of insulin resistance.
In a small study Maddux et al were able to demonstrate with 23 non-diabetic patients, that IGFBP-1 serum concentration correlated very well with Glucose-uptake rate, even better than the HOMA index does.

-Pregnancy
In pregnancy a significant difference in IGFBP-1 serum concentration of healthy pregnant and diabetic and pre-eclamptic women was found (102,8 vs. 203,71 oder 281,09 ng/ml respectively).
Also the evaluation of IGFBP-1 as marker for membrane rupture showed a high specificity (97%) and sensitivity (75%) of IGFBP-1 in vaginal/cervical secrets. In this study IGFBP-1 concentrations of >100 ng/ml were set as threshold for detection of amnion fluid and therewith diagnosis of membrane rupture. A positive predictive value of 97% clearly shows that IGFBP-1 is a suitable marker for premature membrane rupture.

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