title: Glucose-induced insulin secretion in uremia: effects of aminophylline infusion and glucose loads.
abstract: To explain mechanisms responsible for derangement of insulin release in uremia, we investigated glucose metabolism through three different tests in 14 patients with end-stage chronic renal failure. These tests were: intravenous glucose tolerance test with 0.33 g/kg of glucose solution (IVGTT); IVGTT with 0.5 g/kg of glucose solution (IVGTT2); IVGTT during aminophylline infusion (IVGTT + A). Twelve of the patients had IVGTT repeated after two to four months of thrice-weekly regular hemodialysis (IVGTT3). In each test we measured plasma glucose (G), immunoreactive insulin (IRI) and C-peptide. We also calculated glucose constant decay (K), insulin production (IRI area), insulinogenic index (IGI), and insulin resistance index (RI). Twenty-nine healthy volunteers formed the normal controls for IVGTT. As compared to controls, during IVGTT uremic patients showed significantly lower values in K, IRI area and IGI, and showed a significant RI value increase. During IVGTT2, IRI are values were higher than during IVGTT but IGI and K values were unchanged. During IVGTT + A both IRI area and IGI values were higher than during IVGTT. After hemodialysis treatment (IVGTT3) K, IRI areas and IGI increased significantly as compared to the predialysis period. K increase after hemodialysis correlated directly to IGI increase and inversely to RI changes. IGI increase during IVGTT3 was directly correlated to IGI rise during IVGTT + A. From these data we infer that defective insulin release in uremia is due to a decrease of beta-cell glucose sensitivity rather than to their functional exhaustion. An impaired adenyl cyclase-cAMP system may have an important role in the pathogenesis of this abnormality.
authors.affiliation: Servizio Emodialisi, Ospedale di Palmanova, USL No.8 Bassa Friuland, Regione Friuli-Venezia Giulia, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Allegra
authors.forename: G
authors.initials: G
authors.lastname: Mengozzi
authors.forename: L
authors.initials: L
authors.lastname: Martimbianco
authors.forename: A
authors.initials: A
authors.lastname: Vasile
mesh_terms: D000628:Aminophylline; D001786:Blood Glucose / Q000378:metabolism*; D000242:Cyclic AMP / Q000502:physiology; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D014511:Uremia / Q000503:physiopathology* / Q000628:therapy
chemical_list: D001786:Blood Glucose; D007328:Insulin; D000628:Aminophylline; D000242:Cyclic AMP