Residual β cell function in insulin-dependent diabetes: evaluation by circadian determination of C-peptide immunoreactivity

Abstract

Residual beta cell function was evaluated through circadian determination of C-peptide immunoreactivity (CPR) in eighty insulin-dependent diabetics. Evaluation of beta cell activity through circadian CPR determination was in good agreement with the results obtained by glucagon test which is considered a potent stimulus of C-peptide release. The prevalence of residual beta cell function in our population was 35%. Residual beta cell function was associated with a shorter duration of diabetes, a lower dose of insulin therapy and less chronic complications. On the other hand, serum growth hormone circadian variations were more spread in diabetics without beta cell function. That is consistent with diabetes instability which has been reported more commonly insulin-dependent diabetics without beta cell function.

Regulatory and molecular aspects of mammalian amino acid transport

“…In all these conditions the responsiveness of System A to glucagon was also impaired. Glucagon also up-regulates System A activity in liver parenchymal cells when administed either in vitro [33,59] or in vivo [60][61][62][63][64][65]. The action of insulin and glucagon on liver System A activity is an exception to the classical view that these pancreatic hormones exert opposite effects on liver metabolism.…”

“…Catecholamines up-regulate System A activity in liver parenchymal cells predominantly through a-receptors [65]. Adrenalin also induces System A activity in isolated rat hepatocytes from fetuses and from neonates [51].…”

Evidence of an accelerated B-cell destruction in HLA-Dw3/Dw4 heterozygous children with Type 1 (insulin-dependent) diabetes

“…The possible relationship between HLA antigens and residual B cell function in Type 1 diabetes in controversial [7]. Recently Hoogwerf et al [8] have demonstrated an increased meal-stimulated C-peptide response in HLA-DR4 positive diabetic patients, whereas some other studies have failed to show any correlation between HLA determinants and circulating C-peptide concentrations [9,10].…”