Insulin resistance and insulin deficiency in the pathogenesis of posttransplantation diabetes in man.

Although steroids can induce insulin resistance, it is not known whether additional defects in insulin secretion are necessary for the development of diabetes. To address this question, we measured insulin sensitivity (euglycemic insulin clamp in combination with indirect calorimetry and infusion of tritiated glucose) and insulin secretion (hyperglycemic clamp) in three groups of subjects: (1) 10 kidney transplant patients with normal oral glucose tolerance, (2) 14 patients who developed diabetes after kidney transplantation, and (3) 10 healthy controls. Glucose utilization, primarily storage of glucose as glycogen, was reduced by 34% in kidney transplant patients with normal glucose tolerance when compared with healthy control subjects (18.2 +/- 2.9 vs. 27.5 +/- 2.7 microM/L; P less than 0.05). Insulin secretion was normal in relation to the degree of insulin resistance in transplanted non-diabetic patients, thus maintaining a normal oral glucose tolerance. Development of transplantation diabetes was associated with only minor further deterioration of glucose storage (14.7 +/- 2.7 microM/L; P less than 0.001 vs. control subjects), whereas first-phase, second-phase, and glucagon-stimulated insulin secretion measured during hyperglycemic clamping (incremental area under the insulin curve 287 +/- 120, 1275 +/- 419, and 3515 +/- 922 pM) became impaired as compared with nondiabetic kidney transplant patients (769 +/- 216, 3084 +/- 545, and 6293 +/- 533 pM; P less than 0.05). We conclude that both insulin resistance and insulin deficiency are necessary for the development of diabetes in kidney transplant patients.

Effect of steroid-therapy on insulin sensitivity in insulin-dependent diabetic patients after kidney transplantation.

Little information is available on glucose and energy metabolism in insulin-dependent diabetes mellitus (IDDM) patients receiving immunosuppression after kidney transplantation. We therefore measured insulin sensitivity (euglycemic insulin clamp in combination with indirect calorimetry and infusion of tritiated glucose) in (a) eight steroid-treated IDDM patients after kidney transplantation, (b) ten IDDM patients without nephropathy, (c) ten nondiabetic patients after kidney transplantation, and (d) ten healthy control subjects. Hepatic glucose production was enhanced in both steroid-treated transplanted IDDM patients [4.8 +/- 0.6 mg/kg lean body mass (LBM).min] and IDDM patients without complications (3.8 +/- 0.2 mg/kg LBM.min) compared with nondiabetic renal graft recipients and with healthy controls (2.8 +/- 0.2 and 2.7 +/- 0.1 mg/kg LBM.min; p less than 0.01). Insulin-stimulated glucose disposal was reduced in transplanted and non-transplanted IDDM patients and nondiabetic transplanted patients versus healthy controls (6.6 +/- 0.8, 5.7 +/- 0.7, and 7.5 +/- 0.6 versus 9.3 +/- 0.6 mg/kg LBM.min; p less than 0.05). This reduction was mainly due to an impairment in nonoxidative glucose metabolism, i.e., glycogen synthesis (3.1 +/- 0.6, 2.7 +/- 0.4, and 3.3 +/- 0.5 versus 5.0 +/- 0.5 mg/kg LBM.min; p less than 0.05 versus healthy controls). It is concluded that IDDM patients without nephropathy show both hepatic and peripheral insulin resistance. In IDDM patients a further increase of insulin resistance caused by treatment with corticosteroids can be corrected by increased insulin doses. However, nondiabetic steroid-treated renal graft recipients show insulin resistance comparable to IDDM patients.

Insulin resistance precedes microalbuminuria in patients with insulin-dependent diabetes mellitus.

BACKGROUND: Insulin resistance has been associated with hypertension and with renal complications in patients with type 1 diabetes mellitus. Causal relationships have not been fully explained. METHODS: We investigated whether insulin resistance precedes microalbuminuria by measuring insulin resistance with a euglycaemic clamp in combination with indirect calorimetry in 16 uncomplicated type 1 diabetic patients and in six healthy control subjects. The patients had over 10 year duration of diabetes, and were expected to experience either a complication-free or complicated disease course within the next few years. They have thereafter been followed for the development of microalbuminuria for 3 years. RESULTS: In a euglycaemic insulin clamp glucose disposal was lower in diabetic patients compared with control subjects (7.5 +/- 2.9 and 12.6 +/- 2.0 mg/kg LBM/min; P<0.002), mainly due to impaired glucose storage (4.3 +/- 2.3 vs 8.6 +/- 1.6 mg/kg LBM/min; P<0.001). Three years later seven IDDM patients had albumin excretion rate over 30 mg/24 h; glucose disposal (5.5 +/- 2.1 vs 9.0 +/- 2.2 mg/kg LBM/min; P<0.01) had been lower in patients who developed microalbuminuria compared with those who remained normoalbuminuric. CONCLUSIONS: Insulin resistance predicts the increment in urinary albumin excretion. Insulin resistance depends mainly on impaired glucose storage in uncomplicated IDDM.

The relationship between first-phase insulin secretion and glucose metabolism.

A possible pathogenetic link between absence of first-phase insulin secretion and development of impaired glucose metabolism has been suggested by the results of several cross-sectional studies. First-phase insulin secretion measured during a +7 mmol/l hyperglycemic glucose clamp correlated with total glucose disposal during the clamp (r = 0.65, p < 0.001, N = 59). To examine whether restoration of first-phase insulin secretion improves peripheral glucose uptake in subjects with impaired glucose utilization, seven insulin-resistant subjects (age 54 (38-62) years: BMI 29.3 (21.7-35.8); fasting plasma glucose 5.5 (4.8-7.2) mmol/l; fasting insulin 57 (37-105) pmol/l with impaired first-phase (148 (29-587) vs controls 485 (326-1086) pmol/l x 10 min; p < 0.05) and normal second-phase (1604 (777-4480) vs controls (1799 (763-2771) pmol/l x 110 min) insulin secretion were restudied. The impaired first-phase insulin secretion was restored by an iv insulin bolus at the start of the hyperglycemic clamp. Substrate oxidation rates and hepatic glucose production were determined by indirect calorimetry and [3-3H]glucose infusion. Total glucose uptake was impaired in the insulin-resistant subjects with impaired first-phase insulin secretion compared to controls (18.8 (13.2-22.2) vs 34.8 (24.3-62.1) mumol.kg-1 x min-1; p < 0.01). Restoration of first-phase insulin secretion (1467 (746-2440) pmol/l x 10 min) did not affect glucose uptake (20.2 (9.9-23.8) mumol.kg-1.min-1), with no difference in oxidative and non-oxidative glucose metabolism between the experiments. Second-phase insulin secretion was similar during both experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Insulin resistance and abnormal albumin excretion in non-diabetic first-degree relatives of patients with NIDDM.

Microalbuminuria has recently been associated with insulin resistance in both insulin-dependent and non-insulin-dependent (NIDDM) diabetes mellitus. To establish whether microalbuminuria in non-diabetic subjects as well is associated with insulin resistance and associated abnormalities in glucose and lipid metabolism, oral glucose tolerance tests were performed with measurement of urinary albumin excretion rate, lipids and lipoproteins in 582 male non-diabetic first-degree relatives of patients with NIDDM. In addition, insulin sensitivity was assessed in 20 of these subjects with the euglycaemic hyperinsulinaemic clamp technique. Abnormal albumin excretion rate (AER), defined as AER 15-200 micrograms/min, was associated with higher systolic blood pressure (p < 0.05), higher fasting glucose values (p < 0.05), lower HDL-cholesterol (p < 0.05) and lower apolipoprotein A-I (p < 0.05) concentrations than observed in subjects with normal AER. The rate of glucose metabolism was lower in subjects with abnormal compared to subjects with normal albumin excretion rate (38.0 +/- 2.8 vs 47.3 +/- 2.4 mumol.kg lean body mass-1.min-1; p = 0.028). This difference was almost completely accounted for by a reduction in non-oxidative glucose metabolism (17.7 +/- 1.9 vs 27.4 +/- 2.7 mumol.kg lean body mass-1.min-1; p = 0.010), which correlated inversely with the AER (r = -0.543; p = 0.013). These results suggest that in non-diabetic individuals genetically predisposed to NIDDM, abnormal AER is associated with insulin resistance and abnormalities in glucose and lipid metabolism.