Human FGF-21 ELISA Kit - Quantikine Best Seller

Name: Human FGF-21 Quantikine ELISA Kit
Brand: R&D Systems
SKU: DF2100
Rating: 4 (6 reviews)

R&D Systems, part of Bio-Techne | Catalog # DF2100

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Citations (112)

Product Datasheet / COA / SDS

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Product Summary
Product Specifications
Sample Values
Precision
Recovery
Linearity
Scientific Data
Preparation & Storage
Background
Product Documents
Specific Notices

Key Product Details

Assay Length

4.5 hours

Sample Type & Volume Required Per Well

Cell Culture Supernates (50 µL), Serum (50 µL), EDTA Plasma (50 µL), Heparin Plasma (50 µL)

Sensitivity

8.69 pg/mL

Assay Range

31.3-2000 pg/mL (Cell Culture Supernates, Serum, EDTA Plasma, Heparin Plasma)

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Product Summary for Human FGF-21 Quantikine ELISA Kit

The Quantikine Human FGF-21 Immunoassay is a 4.5 hour solid-phase ELISA designed to measure human FGF-21 in cell culture supernates, serum, and plasma. It contains E. coli-expressed recombinant human FGF-21 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human FGF-21 showed linear curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for naturally occurring human FGF-21.

Product Specifications

Assay Type

Solid Phase Sandwich ELISA

Format

96-well strip plate

Measurement

Quantitative ELISA

Detection Method

Colorimetric - 450nm (TMB)

Conjugate

HRP

Reactivity

Human

Specificity

Natural and recombinant human FGF-21

Cross-reactivity

< 0.5% cross-reactivity observed with available related molecules. < 50% cross-species reactivity observed with species tested.

Interference

No significant interference observed with available related molecules.

Sample Values

Serum/Plasma - Samples from apparently healthy volunteers were evaluated for the presence of human FGF-21 in this assay. No medical histories were available for the donors used in this study.

Sample Type	Mean of Detectable (pg/mL)	% Detectable	Range (pg/mL)
Serum (n=35)	172	97	ND-914
EDTA plasma (n=35)	201	97	ND-1155
Heparin plasma (n=35)	186	97	ND-1012

ND=Non-detectable

Cell Culture Supernates - Human peripheral blood leukocytes (PBLs) were cultured in DMEM supplemented with 5% fetal bovine serum, 5 μM beta-mercaptoethanol, 2 mM L-glutamine, 100 U/mL penicillin, and 100 μg/mL streptomycin sulfate. Cells were cultured unstimulated or stimulated with 10 μg/mL PHA. Aliquots of the cell culture supernate were removed and assayed for human FGF-21. No detectable levels were observed.

Precision

Intra-Assay Precision (Precision within an assay) Three samples of known concentration were tested on one plate to assess intra-assay precision.

Inter-Assay Precision (Precision between assays) Three samples of known concentration were tested in separate assays to assess inter-assay precision.

Cell Culture Supernates, EDTA Plasma, Heparin Plasma, Serum

	Intra-Assay Precision			Inter-Assay Precision
Sample	1	2	3	1	2	3
n	20	20	20	40	40	40
Mean (pg/mL)	204	672	1324	245	742	1411
Standard Deviation	8.0	19.8	46.2	26.6	47.2	73.9
CV%	3.9	2.9	3.5	10.9	6.4	5.2

Recovery for Human FGF-21 Quantikine ELISA Kit

The recovery of FGF-21 spiked to levels throughout the range of the assay in various matrices was evaluated.

Sample Type	Average % Recovery	Range %
Cell Culture Media (n=4)	98	93-108
EDTA Plasma (n=4)	103	92-112
Heparin Plasma (n=4)	98	83-111
Serum (n=4)	105	87-119

Linearity

To assess the linearity of the assay, samples spiked with high concentrations of FGF-21 were serially diluted with the Calibrator Diluent to produce samples with values within the dynamic range of the assay.

Scientific Data Images for Human FGF-21 Quantikine ELISA Kit

Human FGF-21 ELISA Standard Curve

Preparation and Storage

Shipping

The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.

Stability & Storage

Store the unopened product at 2 - 8 °C. Do not use past expiration date.

Background: FGF-21

Fibroblast growth factor 21 (FGF-21) is a member of the FGF gene family, which contains 22 mammalian members. Based on its structure, it is further classified as a member of the FGF-19 subfamily, which also includes FGF-19 and FGF-23 (1-4). FGF family members contain a 120 amino acid (aa) core FGF domain that exhibits a beta-trefoil structure. FGF-19 subfamily members, unlike other FGFs, lack one strand of the beta-trefoil and bind poorly to extracellular matrix molecules such as heparin (3). They are consequently more diffusible than other FGFs and are considered endocrine rather than paracrine (1-4). All three subfamily members impact some aspect of metabolism; all three are induced by a nuclear receptor heterodimer that includes RXR (retinoid X receptor), and all three bind FGF receptors (FGF R) indirectly through co-receptors of the klotho family (5-9). FGF-21 binds to beta-Klotho via its C-terminal sequence. This binding, along with amino acids at the N-terminus, is required for signaling through FGF R (7, 8). FGF-21 is selective for FGF R1 isoform 1c, with varying reports of using isoforms 2c or 3c (10-12). Presence of the required klotho and FGF R family members determines tissue specificity of FGF-19 subfamily members, and thus concentrates FGF-21 activity within adipose tissue (3, 9-11). Mature human FGF-21 shares 81% aa sequence identity with mouse and rat FGF-21.

FGF-21 is produced by hepatocytes in response to free fatty acid (FFA) stimulation of a PPAR alpha/RXR dimeric complex (4, 13-15). This situation occurs during starvation, diabetic ketosis, or following the ingestion of a high-fat/low-carbohydrate or ketogenic diet (5, 14-16). Upon FGF-21 secretion, white adipose tissue is induced to release FFAs from triglyceride stores. Once FFAs reach the hepatocytes, they are oxidized and reduced to acetyl-CoA (16). The acetyl-CoA is recombined into 4-carbon ketone bodies (acetoacetate and beta-hydroxybutyrate), released, and transported to peripheral tissues for energy generation (5, 15, 16). FGF-21 production is also induced upon differentiation of human or mouse fibroblasts to adipocytes (17, 18). In adipose tissue, FGF-21 induces glucose uptake by signaling in synergy with PPAR gamma to increase production of the glucose transporter, GLUT1 (10, 12, 19).

FGF-21 production follows a circadian pattern in mice (20). It diffuses across the blood-brain barrier and this may facilitate induction of a state of torpor, or decreased activity, in response to increased FGF-21 (16, 21). These characteristics appear to induce a hibernation-like state during fasting and short days in winter (22). In diet-induced obese mice and mouse models of diabetes such as db/db and ob/ob, administration or transgenic overexpression of FGF-21 restores circulating glucose and triglyceride values to near normal and increases insulin sensitivity (5, 6, 14, 23, 24). In some of these states and in human obesity and type II diabetes, FGF-21 is already elevated prior to treatment, suggesting that resistance to FGF-21 is possible (17, 25, 26). Although FGF-21 administration corrects obesity in mice, it is unclear whether the same benefit would be seen in humans (2, 3, 17, 26-28).

Long Name

Fibroblast Growth Factor 21

Alternate Names

FGF21

Entrez Gene IDs

26291 (Human); 56636 (Mouse)

Gene Symbol