Rodent IGF-I ELISA Assay


The Rodent IGF-I ELISA Assay is to be used for the measurement of IGF-I in mouse/rat serum and plasma. The Eagle Biosciences Mouse/Rat IGF-I ELISA Assay kit is for Research Use Only.

Rodent IGF-I ELISA Assay

The Rodent IGF-I ELISA Assay is For Research Use Only

Size: 1×96 wells
Sensitivity: 0.029 ng/ml
Incubation Time: 2 hours
Sample Type: Serum, Plasma
Sample Size: 10 ul

Product is manufactured by Mediagnost

Assay Principle

The Eagle Biosciences ELISA for mouse/rat IGF-I E25 is a so-called Sandwich-Assay. It utilizes two specific and high affinity antibodies for this protein. The IGF-I in the sample binds to the immobilized first antibody on the microtiter plate, the biotinylated and Streptavidin-Peroxidase conjugated second specific anti-IGF-I-Antibody binds in turn to the immobilized IGF-I. In the closing substrate reaction the turn of the colour will be high specific catalysed, quantitatively depending on the IGF-I-level of the samples.

In order to dissociate IGF-I from the IGFBPs, the samples must be diluted in an acidic buffer (Figure 2). The diluted samples are then pipetted into the wells, by this the pH-value will be neutralized. After neutralization of the samples, the excess IGF-II occupies the IGF-binding sites of the binding proteins, thus allowing the measurement of resulting free IGF-I. With this method, the IGFBPs are not removed, but their function and therefore their interference in the assay is neutralized. Due to the extremely low cross-reactivity of the IGF-I antibody with IGF-II, the excess of IGF-II does not disturb the interaction with IGF-I. The test runs like a conventional ELISA using a Streptavidin-Peroxidase-Enzyme Conjugate.

Related Products

Rodent IGFBP-2 ELISA Assay
Rodent IGFBP-3 ELISA Assay

Additional Information

Assay Background

Beside different cell culture models and studies with human patients, mice and rats are suitable model organisms for basic research and pre-clinical studies.Thus, we developed this test system as a tool for IGF-I measurements in mice and rat for usage in research and pre-clinical studies. Even if the comparability of mice and humans is limited we offer some background information on the human IGF-I system in the following section:
Insulin-like growth factors (IGF) I and II play a pivotal role in regulating the proliferation and differentiation of many cell types (1-3). IGF-I is identical with Somatomedin C (Sm-C) (4) and has a molecular weight of 7649 daltons (5). Its major regulators are growth hormone (GH) and nutrition (6). In contrast to many other peptide hormones, IGFs are avidly bound to specific binding proteins (IGFBP). The seven IGFBPs which are known at present (7,8,22) either bind IGF-I and IGF-II with similar affinities or show a preference for IGF-II (9,10).
A major problem of IGF-I measurement results from the interference of IGFBPs in the assay. Direct determinations in untreated serum samples (11) give false values because of the extremely slow dissociation of the IGF-I/IGFBP-3 complexes during the assay incubation. Depending on the ratio IGF-I to IGFBP in the sample interference comes up.

Therefore, various techniques were applied to physically separate IGF-I from its binding proteins before measurement, including (a) size exclusion chromatography under acidic conditions, (b) solid-phase extraction and (c) acid-ethanol extraction (2,12,13). These techniques, however, are either inconvenient or time-consuming or give incomplete and not-reproducible recoveries. The most widely used method is the acid-ethanol extraction (13,14) with a recovery of only 70-80 % of IGFBP-bound IGF-I as a result of co-precipitation. The absolute results of such an extraction are therefore false low (15). The extraction removes the IGFBPs only insufficiently and leads to reduction in sensitivity of the assay due to pre-dilution of the samples by the extraction procedure. Furthermore, the remaining IGFBP may still interfere in the assay. In addition, the acid-ethanol extraction is ineffective in specimens other than serum or plasma (e.g. cell culture media), in which determination of IGF-I is already difficult enough due to the fact that IGFBPs are frequently present at large excess. To avoid these difficulties, an uncomplicated assay was developed, in which special sample preparation is not required before measurement.

Standard Curve

Rodent IGF-I ELISA Assay

Exemplary Standard Curve with a polynomial 3rd degree as curve fit.

Package Inserts

Please note: All documents above are for reference use only and should not be used in place of the documents included with this physical product. If digital copies are needed, please contact us.

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