Insulin (HMV308)

Insulin is an 5,8 kDa peptide hormone composed of 51 amino acids coded by the insulin (INS) gene at 11p15.5. Insulin is the main anabolic hormone of the body. It is only produced in beta cells of the pancreatic islets and its production level is dependent on the blood glucose level. Pancreatic beta cells are sensing the serum glucose levels and secrete insulin in response to a high serum level of glucose, while low glucose levels inhibit insulin secretion. Insulin regulates the metabolism of carbohydrates and fat by promoting the absorption of glucose from the blood into liver, fat and skeletal muscle cells where it is converted into glycogen and/or triglycerides. Insulin also regulates protein synthesis in various tissues. Low serum insulin levels have the opposite effect and result in catabolism, especially of body fat. Decreased or absent insulin results in diabetes mellitus, a condition of high blood glucose (hyperglycaemia).

Images describing the insulin staining pattern in normal tissues obtained by the antibody HMV308 are shown in our “Normal Tissue Gallery”.

In normal tissues, insulin is only produced in islet cells of the pancreas

These findings are fully consistent with the RNA data described in the Human Protein Atlas (Tissue expression Insulin) which also describe insulin expression to be limited to the pancreas.

Positive control = Pancreas: A strong insulin staining should be seen in a large fraction of islet cells.

Negative control = Colon: Insulin staining must be absent in all cell types.

Normal tissue gallery

Cancer tissue gallery

No data available at the moment

IHC users have different preferences on how the stains should look like. Some prefer high staining intensity of the target stain and even accept some background. Others favor absolute specificity and lighter target stains. Factors that invariably lead to more intense staining include higher concentration of the antibody and visualization tools, longer incubation time, higher temperature during incubation, higher temperature and longer duration of the heat induced epitope retrieval (slide pretreatment). The impact of the pH during slide pretreatment has variable effects and depends on the antibody and the target protein.

All images and data shown here and in our image galleries are obtained by the manual protocol described below. Other protocols resulting in equivalent staining are described as well.

Manual protocol

Freshly cut sections should be used (less than 10 days between cutting and staining). Heat-induced antigen retrieval for 5 minutes in an autoclave at 121°C in pH 7,8 Target Retrieval Solution buffer. Apply HMV308 at a dilution of 1:150 at 37°C for 60 minutes. Visualization of bound antibody by the EnVision Kit (Dako, Agilent) according to the manufacturer’s directions.

• -To what extent ectopic production of insulin can occur in cancer has not been analyzed.

There are two ways how the specificity of antibodies can be documented for immunohistochemistry on formalin fixed tissues. These are: 1. Comparison with a second independent method for target expression measurement across a large number of different tissue types (orthogonal strategy), and 2. Comparison with one or several independent antibodies for the same target and showing that all positive staining results are also seen with other antibodies for the same target (independent antibody strategy). 

Orthogonal validation: For the antibody HMV308, staining specificity for insulin is demonstrated by the complete concordance of the immunostaining data with data from three independent RNA screening studies, including the Human Protein Atlas (HPA) RNA-seq tissue dataset, the FANTOM5 project, and the Genotype-Tissue Expression (GTEx) project, which are all summarized in the human protein atlas. Insulin immunostaining by HMV308 is only seen in the pancreas (islet cells), the only organ for which insulin RNA expression had previously been documented.

Normal tissue gallery