Arginine Metabolism Is Altered in Adults with A-? + Ketosis-Prone Diabetes.
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ABSTRACT: Background:A-? + ketosis-prone diabetes (KPD) is a subset of type 2 diabetes in which patients have severe but reversible ? cell dysfunction of unknown etiology. Plasma metabolomic analysis indicates that abnormal arginine metabolism may be involved. Objective:The objective of this study was to determine the relation between gut microbiome and arginine metabolism and the relation between arginine availability and ? cell function in KPD patients compared with control participants. Methods:Kinetics of arginine and related metabolites were measured with stable isotope tracers, and insulin secretory responses to arginine and glucose were determined under euglycemic and hyperglycemic conditions in 6 KPD patients and 6 age-, gender-, and body mass index-matched control participants. Glucose potentiation of arginine-induced insulin secretion was performed in a different set of 6 KPD and 3 control participants. Results:Arginine availability was higher in KPD patients during euglycemia [53.5 ± 4.3 (mean ± SEM) compared with 40.3 ± 2.4 ?mol · kg lean body mass (LBM)-1 · h-1, P = 0.03] but declined more in response to hyperglycemia (? 10.15 ± 2.6 compared with ? 3.20 ± 1.3 ?mol · kg LBM-1 · h-1, P = 0.041). During hyperglycemia, ornithine flux was not different between groups but after an arginine bolus, plasma ornithine AUC trended higher in KPD patients (3360 ± 294 compared with 2584 ± 259 min · ?mol · L-1, P = 0.08). In both euglycemia and hyperglycemia, the first-phase insulin responses to glucose stimulation were lower in KPD patients (euglycemic insulin AUC 282 ± 108 compared with 926 ± 257 min · ?U · mL-1, P = 0.02; hyperglycemic insulin AUC 358 ± 79 compared with 866 ± 292 min · ?U · mL-1, P = 0.05), but exogenous arginine restored first-phase insulin secretion in KPD patients to the level of control participants. Conclusion:Compared with control participants, KPD patients have increased arginine availability in the euglycemic state, indicating a higher requirement. This is compromised during hyperglycemia, with an inadequate supply of arginine to sustain metabolic functions such as insulin secretion. Exogenous arginine administration restores a normal insulin secretory response.
SUBMITTER: Mulukutla SN
PROVIDER: S-EPMC6251649 | biostudies-literature | 2018 Feb
REPOSITORIES: biostudies-literature
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