The fasting proinsulin-to-insulin ratio is a currently used marker of beta-cell dysfunction. This ratio is calculated at the basal condition, but its behavior in dynamic conditions, i.e., during glucose stimulation, could be more informative. Given the different kinetics of the peptides, a mathematical model was necessary to analyze the oral glucose tolerance test (OGTT) data of insulin, C-pept...

Insulin, proinsulin, and C-peptide levels increase with sulfonylurea exposure but the acuity of increase has not been described in dialysis patients. We present a case of a dialysis patient who presented with hypoglycemia and was found to have accidental sulfonylurea ingestion. This is a 73-year-old man with ESRD on peritoneal dialysis, without history of diabetes, who presented with hypoglycem...

We have chosen a vertebrate model accessible during neurulation, the chick, for analysis of endogenous insulin signaling and its contribution to early embryonic cell survival. Unlike rodents, humans and chickens have a single preproinsulin gene, facilitating its prepancreatic expression characterization. We show that in vivo interference with embryonic insulin signaling using antisense oligonuc...

Hyperinsulinemia is associated with the development of coronary heart disease. However, the underlying mechanisms are still poorly understood. Hypercoagulability and impaired fibrinolysis are possible candidates linking hyperinsulinism with atherosclerotic disease, and it has been suggested that proinsulin rather than insulin is the crucial pathophysiological agent. The aim of this study was to...

We examined the effects of rat islet amyloid polypeptide (IAPP) on insulin biosynthesis and secretion by isolated rat islets of Langerhans. Culture of islets for 24 h in the presence of 10(-6) M IAPP and 5.5 mM glucose had no effect on insulin mRNA levels. Similarly, the rates of proinsulin biosynthesis were not altered in islets incubated in 10(-4)-10(-9) M IAPP and 5.5 mM glucose, nor was the...

OBJECTIVE We evaluated the respective value of insulin, C-peptide and proinsulin levels in 33 patients with endogenous hyperinsulinism and in 67 controls to determine the best parameters and thresholds to make or to rule out the diagnosis of endogenous hyperinsulinism. RESULTS When blood glucose levels were below 2.5 mmol/l, insulin was <21 pmol/l in 8-35% of the patients and in all controls;...

INTRODUCTION To investigate how markers of β-cell secretion (proinsulin-processing metabolites) are expressed in rheumatoid arthritis (RA) patients and their potential relation with the insulin resistance (IR) observed in these patients. METHODS The 101 RA patients and 99 nondiabetic sex- and age-matched controls were included. IR by homeostatic model assessment (HOMA2), and β-cell secretion,...

OBJECTIVE One putative benefit of hormone replacement therapy (HRT) is a reduced risk of diabetes or reduced fasting glucose level. We report here the association of HRT with proinsulin, insulin, and fasting and postchallenge glucose levels in older adults. RESEARCH DESIGN AND METHODS Current HRT use was validated and cross-sectionally compared with diabetes-related variables in 785 women wit...

Mycobacterium avium subspecies paratuberculosis (MAP) asymptomatic infection is speculated to play a role in type 1 diabetes (T1D) among Sardinian subjects. Data obtained analyzing a pediatric population from mainland Italy lends support to the hypothesis, which envisions MAP as an environmental factor at play in T1D pathogenesis. Aiming to investigate the likelihood of cross-recognition betwee...