Insulin secretion in lipodystrophic HIV-infected patients is associated with high levels of nonglucose secretagogues and insulin resistance of beta-cells.

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Steen B Haugaard, Ove Andersen, Heidi Storgaard, Flemming Dela, Jens Juul Holst, Johan Iversen, Jens Ole Nielsen, Sten Madsbad

We examined whether plasma concentrations of nonglucose insulin secretagogues are associated with prehepatic insulin secretion rates (ISR) in nondiabetic, insulin-resistant, human immunodeficiency virus (HIV)-infected, lipodystrophic patients (LIPO). Additionally, the negative feedback of insulin on ISR was evaluated. ISR were estimated by deconvolution of plasma C-peptide concentrations during fasting (basal) and during the last 30 min of a 120-min euglycemic insulin clamp (40 mU.m(-2).min(-1)). Eighteen normoglycemic LIPO were compared with 25 normoglycemic HIV-infected patients without lipodystrophy (controls). Thirty minutes before start of the clamp, a bolus of glucose was injected intravenously to stimulate endogenous insulin secretion. Insulin sensitivity index (SiRd) was estimated from glucose tracer analysis. LIPO displayed increased basal ISR (69%), clamp ISR (114%), basal insulin (130%), and clamp insulin (32%), all P < or = 0.001, whereas SiRd was decreased (57%, P < 0.001). In LIPO, ISRbasal correlated significantly with basal insulin, alanine, and glucagon (all r > 0.65, P < 0.01), but not with glucose. In control subjects, ISR(basal) correlated significantly with insulin, glucagon, and glucose (all r > 0.41, P < 0.05), but not with alanine. In LIPO, ISRclamp correlated significantly with clamp free fatty acids (FFA), alanine, triglyceride, and glucagon (all r > 0.51, P < 0.05). In control subjects, ISRclamp correlated with clamp triglyceride (r = 0.45, P < 0.05). Paradoxically, in LIPO, ISRclamp correlated positively with clamp insulin (r = 0.68, P < 0.01), which suggests an absent negative feedback of insulin on ISR. Our data support evidence that lipodystrophic, nondiabetic, HIV-infected patients exhibit increased ISR, which can be partially explained by an impaired negative feedback of insulin on beta-cells and an increased stimulation of ISR by FFA, alanine, triglyceride, and glucagon.
Original languageEnglish
JournalAmerican Journal of Physiology: Endocrinology and Metabolism
Issue number4
Pages (from-to)E677-85
Number of pages9
Publication statusPublished - 2004

Bibliographical note

Keywords: Adipose Tissue; Adult; Alanine; Anthropometry; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Feedback; Glucagon; HIV Infections; HIV-Associated Lipodystrophy Syndrome; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Islets of Langerhans; Male; Middle Aged; Triglycerides

ID: 8418181