Chemiluminescence Immunoassay (LUM) for the determination of Intact Proinsulin in mouse/rat Serum, EDTA-plasma and Heparin-Plasma. For research use only, not for use in diagnostic procedures.<br><br>
Proinsulin is a precursor of insulin that is synthesized in the β cells of the islet of Langerhans of pancreas.<br><br>
Most of the proinsulin synthesized in the rough endoplasmic reticulum of β cells is stored in the secretory granules. It is cleaved by prohormone converting enzyme (PC 2 and PC 3) and it is divided into insulin that consists of 21 amino-acid A chain and 30 amino-acid B chain and C-peptide that consists of 33 amino acid, then it is released in blood by secretory stimulation such as glucose.<br><br>
However, some proinsulin does not enter secretory granules and it is subsequently released in blood as intact (full length) proinsulin without the processing.<br><br>
It has been known that the ratio of proinsulin and insulin (P/I ratio) is an indicator of dysfunction of pancreatic β cell as the ratio of proinsulin become higher due to abnormality of the processing caused by dysfunction of pancreatic β cell. It has been suggested that the P/I ratio is a valuable pancreatic β cell evaluation method that does not require a loading test as it can be measured using blood samples in fasting.<br><br>
This CLEIA kit has a wide measurement range to measure the intact proinsulin at low level in fasting and at high level after loading using only 10 μL sample.