High performance liquid chromatographic analysis of polypeptide hormones in transplanted rat islets

Abstract

This report describes high performance liquid chromatographic analysis of transplanted pancreatic islets. A reversed phase ODS column made it possible to measure rat insulin I, II, rat C-peptide I, II and glucagon simultaneously in isolated rat islets without using radioisotopes. Freshly isolated islets contained 118.0 +/- 9.7 ng (mean +/- SE, n = 6) insulin and 3.01 +/- 0.60 ng glucagon per islet. The insulin I/II ratio was 1.22 +/- 0.03. Isolated islets were then cultured in vitro or transplanted into mice under the renal capsule. Transplantation induced mild hypoglycemia in the recipients. The graft mean survival time was 7.2 +/- 0.4 days (n = 5). Both cultured (n = 7) and transplanted (n = 6) islets showed similar alterations of polypeptide hormones on day 4. Insulin decreased to one third and glucagon remained unchanged. The insulin I/II ratio increased twofold. In conclusion, it was suggested that the general fate of isolated islets was caused by ischemia and denervation. Relatively, ischemia may not damage alpha cells but may damage beta cells because alpha cells are peripherally located. Denervation may release beta cells from a resting state under neural tonic inhibition. Mild hypoglycemia and an increased insulin I/II ratio were related to the accelerated insulin synthesis in the isolated islets.

Stable organic thin film transducers for biochemical and label-free sensing under physiological conditions

“…46 Several analytical methods are available for the detection of insulin, including bioassays, [47][48][49] radioimmunoassays, 50 chemiluminescence immunoassays 51 and immunoenzymometric assays. 52 The most commonly used methods for the detection of insulin are mass spectrometry, 53 photolytic electrochemical detection 54 and high-performance liquid chromatography coupled with UV absorption 55 and fluorescence. 56 These methods are all time consuming; therefore, we wished to employ our OTFTs to detect the charge of insulin.…”

Molecular Dynamics Simulation on Stability of Insulin on Graphene

“…The detection of insulin is of great important for clinical diagnostics, because it is bound up with diabetes and has great applications in clinical pharmacology [21]. Bioassay, immunoassay and chromatographic methods [22] are three main procedures for determination of insulin. Although immunoassay of insulin has been widely used for determination of insulin in biological specimens, non-specific binding with the coexistent biomolecules against antiinsulin antibody and cross reaction are the major interferences with the precise determination of insulin in biosamples [23].…”

Determination of Insulin in a Single Islet of Langerhans by High-Performance Liquid Chromatography with Fluorescence Detection

“…A similar value (118 ng/islet) was observed by HPLC with UV detection utilizing 20 islets. 7 Insulin content in mice (245 ( 59 ng/islet) was observed for the first time, although only the ratio of insulin types I to II obtained from mice was reported by Linde et al with the use of more than 1400 islets. 25 The calculated ratio of types I to II obtained from rats and mice were 1.4 ( 0.2 and 0.57 ( 0.01, respectively, which were consistent with the previous data reported by Linde et al 25 Kakita et al reported that insulin type I is predominant in mice, 26 whereas the result in the present experiment and the data reported by Linde et al 25 showed the predominance of type II.…”

“…In contrast to immunoassays, the chromatographic method is more reliable for selectivity because of the separation step included. High-performance liquid chromatography (HPLC) with UV detection 7 and, more recently, mass spectrometry (MS) with isotope dilution assay (IDA) 8 have been used for the determination of insulin. HPLC with UV detection, however, has poor sensitivity to detect insulin in biological samples; a picomole-level injection on column should be achievable.…”