BACKGROUND Some, but not all, studies have reported a relationship between plasma insulin and coronary heart disease (CHD). Conventional nonspecific insulin assays are also measuring various fractions of proinsulin-like molecules due to cross-reactivity. The long-term relationship between proinsulin-like molecules and CHD is largely unknown. For this reason, the longitudinal relationships betwe...

The cellular itinerary and processing of insulin and proinsulin were studied to elucidate possible mechanisms for the observed in vivo differences in the biologic half-lives of these two hormones. A rat fibroblast cell line transfected with a normal human insulin receptor gene was used. Due to gene amplification, the cells express large numbers of receptors and are ideal for studying a ligand, ...

Elevated proinsulin and proinsulin/insulin ratios are features of abnormal beta-cell function in type 2 diabetes. The participation of genetic factors is disputed. The authors wished to investigate relations between family history of diabetes on one hand and proinsulin as well as proinsulin/immunoreactive insulin ratios on the other. A large, population-based sample of Swedish men aged 35-54 ye...

Abstract.-This communication reports the biosynthesis of insulin in the bovine fetal pancreatic slices in vitro. Double-chain proinsulin and insulin were found as major components in the mitochondrial-granule fraction of bovine fetal pancreas. Tritiated leucine was incorporated into a single-chain proinsulin, a double-chain proinsulin, and insulin. Subcellular fractionation of the slices incuba...

Risk of Coronary Heart Disease in Patients With Diabetes and Prediabetes To the Editor: The evidence relating concentrations of proinsulin to the risk of coronary heart disease is summarized by Haffner and Hanley.1 They point out that few prospective studies have been performed. We have recently published an investigation on the relationship between concentrations of proinsulin-like molecules a...

These studies of partial pancreatectomy assess pancreatic proinsulin messenger RNA (mRNA) levels as an index of in vivo insulin biosynthesis, and show relationships to glucose homeostasis. Rats were subjected to sham operation, 50% pancreatectomy (Px), or 90% Px, and were examined after 1, 3, or 14 wk. Proinsulin mRNA was measured by dot hybridization to complementary DNA. After 50% Px there wa...

OBJECTIVE β-Cells have demonstrated altered proinsulin processing after islet transplantation. We compare β-cell metabolic responses and proinsulin processing in pancreas and islet transplant recipients with respect to healthy control subjects. RESEARCH DESIGN AND METHODS We studied 15 islet and 32 pancreas transplant recipients. Islet subjects were subdivided into insulin-requiring (IR-ISL, ...

In mutant INS gene-induced diabetes of youth (MIDY), characterized by insulin deficiency, MIDY proinsulin mutants misfold and fail to exit the endoplasmic reticulum (ER). Moreover, these mutants bind and block ER exit of wild-type (WT) proinsulin, inhibiting insulin production. The ultimate fate of ER-entrapped MIDY mutants is unclear, but previous studies implicated ER-associated degradation (...

Asian Indians have a unique phenotype characterized by increased abdominal obesity and visceral fat despite low body mass index [BMI]. Though studies have indicated some adipocytokines to be associated with diabetes and obesity in Indians, there are virtually no studies relating adipocytokines and proinsulin with diabetes and obesity in Asian Indians. In this study we looked at adipocytokines--...

The purpose of these experiments was to determine whether insulin-related peptides, larger than proinsulin, could be detected in pancreatic islet cells. Catfish pancreatic islets were incubated with radiolabeled amino acids. After 15- to 60-min incubation, two acid-alcohol-extractable peptides, larger than proinsulin, were detected which were approximately of Mr = 12,000 and 11,000 (12 K and 11...