Improvement of lipid profile in type 2 (non-insulin-dependent) diabetes mellitus by insulin-like growth factor I

Type 2 (non-insulin-dependent) diabetes mellitus is associated with increased glucose, insulin, total and VLDL-triglyceride, and often total and LDL-cholesterol levels which promote vascular disease. Recombinant human insulin-like growth factor-I which mimics many effects of insulin, decreased insulin, total and VLDL-triglyceride, and total and LDL-cholesterol levels in healthy man as well as glucose and insulin levels in Type 2 diabetic patients. We, therefore, investigated total and fractionated triglyceride and cholesterol levels, lipoprotein(a), non-esterified fatty acid, and apolipoprotein levels in eight Type 2 diabetic patients during five control, five treatment, and three wash-out days. They received a constant diet throughout and daily 2 x 120 micrograms insulin-like growth factor-I/kg s.c. during the treatment period. Fasting total and VLDL-triglyceride, total and LDL-cholesterol control levels were (mean +/- SD) 3.1 +/- 2.6, 1.3 +/- 1.0, 6.3 +/- 1.3, and 4.5 +/- 1.1 mmol/l and decreased to 1.6 +/- 0.8, 0.6 +/- 0.4, 5.0 +/- 1.0, and 3.5 +/- 1.1 mmol/l, respectively, on the last treatment day (p < 0.01). During therapy, fasting lipoprotein(a) levels and the postprandial area under the triglyceride curve decreased by 48 +/- 22 and 32 +/- 18% of control (p < 0.01), respectively. In conclusion, insulin-like growth factor-I lowered lipid levels in Type 2 diabetic patients directly or indirectly or both because of decreased glucose and insulin levels. Long-term trials would be of interest with respect to the cardiovascular risk in Type 2 diabetes and patients with hyperlipidaemia.     

Docosahexanoic acid (DHA) improved glucose and lipid metabolism in KK-Ay mice with genetic non-insulin-dependent diabetes mellitus (NIDDM)

The hypoglycemic and hypolipidemic effect of docosahexaenoic acid (DHA; C22: 6omega-3) ethyl ester was examined in KK-Ay mice and neonatal streptozotocin-induced diabetic (NSZ) which are respectively obese and lean animal models of non-insulin-dependent diabetes mellitus (NIDDM), and in ddY normal mice. Single administration of DHA (500 mg/kg body weight) to KK-Ay mice significantly reduced (p<0.05) the blood glucose levels (BG) (p<0.05) and plasma free fatty acid levels (FFA) (p<0.05) at 10 h after oral administration when compared with control group. DHA (500 mg/kg body weight)-treated NSZ and normal mice, however, showed no change in these parameters. In addition, repeated administration of DHA (100 mg/kg) to KK-Ay mice significantly suppressed the increment of BG (p<0.05) and plasma triglyceride levels (TG) (p<0.01), and significantly decreased FFA (p<0.05) at 30 d compared with control group. DHA also significantly decreased the blood glucose at 60 and 120 min on insulin tolerance test (ITT). From these findings, it seems likely that DHA exhibits its hypoglycemic effects by increasing insulin sensitivity. It is concluded that DHA would be useful for treatment of obese type NIDDM with insulin resistance.     

Effects of vanadyl sulfate on carbohydrate and lipid metabolism in patients with non-insulin-dependent diabetes mellitus

Mechanisms for the cell-free activation of NADPH oxidase by sodium dodecyl sulfate (SDS) and arachidonate were compared in relation to their responsiveness to short chain diacylglycerols. The plasma membrane and cytosol prepared from guinea pig neutrophils were used for the cell-free system. The activation of NADPH oxidase by SDS was enhanced about 5- to 10-fold by 1,2-dioctanoylglycerol (diC8), but not by either 1,2-dihexanoylglycerol (diC6) or 1,2-didecanoylglycerol (diC10). However, none of these diacylglycerols potentiated the NADPH oxidase activation by arachidonate. The maximal extent of activation by the combination of SDS and diC8 was similar to that by arachidonate alone. In the presence of sufficient amounts of diC8 and SDS, GTP gamma S potentiated the activation of NADPH oxidase. The potentiating activity of diC8 was preserved in the membrane fraction, not in the cytosol fraction. These results suggest that arachidonate may possess the functions of both SDS and diC8 in the activation. In addition, diC8 and GTP gamma S seem to independently enhance the NADPH oxidase activation.     

Molecular screening of the glucokinase gene in familial type 2 (non-insulin-dependent) diabetes mellitus

The question whether penicillin V (pcV) given intermittently upon signs of upper respiratory tract infections (URTI) in otitis-prone children might prevent recurrent bouts of acute purulent otitis media (AOM) is addressed. As compared with continuous long-term antibiotic treatment as prophylaxis in otitis-prone children, intermittent administration would reduce the overall consumption of antibiotics. Seventy-six otitis-prone children less than 18 months of age were included in this double-blind, randomized, placebo-controlled multicentre study. Follow-up was from January till June. One hundred and twenty-three episodes of AOM occurred. The number of AOM episodes was reduced by 50% in the children on pcV during URTI episodes as compared with those on placebo. No obvious ecological drawbacks were noted. Thus, the described mode of pcV administration seems to be a rational and safe way to reduce the number of AOM episodes in otitis-prone children.     

Characterization of cellular defects of insulin action in type 2 (non-insulin-dependent) diabetes mellitus

Seven non-insulin-dependent diabetes mellitus (NIDDM) patients participated in three clamp studies performed with [3-3H]- and [U-14C]glucose and indirect calorimetry: study I, euglycemic (5.2 +/- 0.1 mM) insulin (269 +/- 39 pM) clamp; study II, hyperglycemic (14.9 +/- 1.2 mM) insulin (259 +/- 19 pM) clamp; study III, euglycemic (5.5 +/- 0.3 mM) hyperinsulinemic (1650 +/- 529 pM) clamp. Seven control subjects received a euglycemic (5.1 +/- 0.2 mM) insulin (258 +/- 24 pM) clamp. Glycolysis and glucose oxidation were quantitated from the rate of appearance of 3H2O and 14CO2; glycogen synthesis was calculated as the difference between body glucose disposal and glycolysis. In study I, glucose uptake was decreased by 54% in NIDDM vs. controls. Glycolysis, glycogen synthesis, and glucose oxidation were reduced in NIDDM patients (P < 0.05-0.001). Nonoxidative glycolysis and lipid oxidation were higher. In studies II and III, glucose uptake in NIDDM was equal to controls (40.7 +/- 2.1 and 40.7 +/- 1.7 mumol/min.kg fat-free mass, respectively). In study II, glycolysis, but not glucose oxidation, was normal (P < 0.01 vs. controls). Nonoxidative glycolysis remained higher (P < 0.05). Glycogen deposition increased (P < 0.05 vs. study I), and lipid oxidation remained higher (P < 0.01). In study III, hyperinsulinemia normalized glycogen formation, glycolysis, and lipid oxidation but did not normalize the elevated nonoxidative glycolysis or the decreased glucose oxidation. Lipid oxidation and glycolysis (r = -0.65; P < 0.01), and glucose oxidation (r = -0.75; P < 0.01) were inversely correlated. In conclusion, in NIDDM: (a) insulin resistance involves glycolysis, glycogen synthesis, and glucose oxidation; (b) hyperglycemia and hyperinsulinemia can normalize total body glucose uptake; (c) marked hyperinsulinemia normalizes glycogen synthesis and total flux through glycolysis, but does not restore a normal distribution between oxidation and nonoxidative glycolysis; (d) hyperglycemia cannot overcome the defects in glucose oxidation and nonoxidative glycolysis; (e) lipid oxidation is elevated and is suppressed only with hyperinsulinemia.     

Insulinoma in a patient with non-insulin-dependent diabetes mellitus

Insulinoma in a patient with pre-existing diabetes is exceedingly rare. Only a small number of well-documented cases have been reported in the world during the last 40 years. We describe a case with non-insulin-dependent diabetes mellitus who after seven years of sulfonylurea treatment experienced recurrent episodes of hypoglycemia. Endogenous hyperinsulinism was found and radiographical examination and transhepatic venous sampling confirmed an insulin secreting pancreatic tumor. After surgical excision of the tumor, patient was relieved from hypoglycemic attacks but required to initiate insulin injection for the treatment of hyperglycemia.     

Postprandial atrioventricular block in a patient with diabetes mellitus

BACKGROUND: The etiology of Peyonie's disease remains a mystery. An attempt is made to resolve this. MATERIALS AND METHODS: A total of 25 patients with Peyronie's disease were examined and investigated for the presence of various implicated etiologic factors. RESULTS: Of the 25 patients examined, two presented with ischemic heart disease, 10 with hypertension, 10 with asymptomatic hyperuricemia, 18 with hypercholesterolemia, two with fibrosing disorders, two with autoimmune disorders, and three with diabetes mellitus. None had any sexually transmitted disease. Seven of the 10 hypertensive patients had received beta-blockers. On comparing the prevalence of these factors between patients and the general population, a significant association was found between hypertension, hypercholesterolemia, hyperuricemia, and Peyronie's disease. CONCLUSIONS: Known factors, such as hypertension and hypercholesterolemia, lead to weakening of the vasculature and its rupture during coitus. This leads to the formation of a hematoma and its subsequent organization in predisposed individuals to fibrous plaques. The identification and treatment of these factors might prevent, secondarily, the development of Peyronie's disease.     

Effects of varying carbohydrate content of diet in patients with non-insulin-dependent diabetes mellitus

OBJECTIVE: To study effects of variation in carbohydrate content of diet on glycemia and plasma lipoproteins in patients with non-insulin-dependent diabetes mellitus (NIDDM). DESIGN: A four-center randomized crossover trial. SETTING: Outpatient and inpatient evaluation in metabolic units. PATIENTS: Forty-two NIDDM patients receiving glipizide therapy. INTERVENTIONS: A high-carbohydrate diet containing 55% of the total energy as carbohydrates and 30% as fats was compared with a high-monounsaturated-fat diet containing 40% carbohydrates and 45% fats. The amounts of saturated fats, polyunsaturated fats, cholesterol, sucrose, and protein were similar. The study diets, prepared in metabolic kitchens, were provided as the sole nutrients to subjects for 6 weeks each. To assess longer-term effects, a subgroup of 21 patients continued the diet they received second for an additional 8 weeks. MAIN OUTCOME MEASURES: Fasting plasma glucose, insulin, lipoproteins, and glycosylated hemoglobin concentrations. Twenty-four-hour profiles of glucose, insulin, and triglyceride levels. RESULTS: The site of study as well as the diet order did not affect the results. Compared with the high-monounsaturated-fat diet, the high-carbohydrate diet increased fasting plasma triglyceride levels and very low-density lipoprotein cholesterol levels by 24% (P < .0001) and 23% (P = .0001), respectively, and increased daylong plasma triglyceride, glucose, and insulin values by 10% (P = .03), 12% (P < .0001), and 9% (P = .02), respectively. Plasma total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels remained unchanged. The effects of both diets on plasma glucose, insulin, and triglyceride levels persisted for 14 weeks. CONCLUSIONS: In NIDDM patients, high-carbohydrate diets compared with high-monounsaturated-fat diets caused persistent deterioration of glycemic control and accentuation of hyperinsulinemia, as well as increased plasma triglyceride and very-low-density lipoprotein cholesterol levels, which may not be desirable.     

Comparison of granulocyte function in diabetes mellitus type 1 and type 2

The phagocytosis rate of polymorphonuclear leucocytes was measured by flow-cytometry. Vital bacteria were incubated in whole blood. 111 blood samples were measured, 54 in diabetic patients (14 type 1 and 40 type 2), the rest of 57 samples in healthy controls. Results showed firstly, that a decompensation in glucose metabolism in diabetic patients correlated with a decrease in phagocytosis. The HbA1 level was more closely correlated than the glucose level. The second result was, that despite a similar grade of decompensation in type 1 and type 2 diabetic patients, the phagocytosis was significantly lower in type 1 diabetes. No correlation was found concerning age and sex. These findings show, that the impact on granulocytic function in diabetes is of multifactorial origin, not only a shorter or longer elevation of the serum glucose level can explain it solely.     

Effect of high fiber intake in fish oil-treated patients with non-insulin-dependent diabetes mellitus

The short-term effect of high fiber intake on fish-oil treatment in 15 free-living, non-insulin-dependent diabetic patients was evaluated by using a controlled, sequential study design. During an 8-wk fish-oil-treatment period when patients received 20 g fish oil/d, the usual daily fiber intake was increased with a 15-g pectin supplement at midpoint. Fish oil alone lowered triacylglycerol and very-low-density-lipoprotein-cholesterol concentrations by 41% and 36%, respectively (both P < 0.01 by the end of the treatment period) with unchanged mean total, low-density-, and high-density-lipoprotein-cholesterol concentrations. When the fiber intake was increased, however, total and low-density-lipoprotein-cholesterol concentrations decreased significantly (P < 0.001 and < 0.05, respectively) with fish-oil treatment. The cholesterol ester fraction of plasma lipids was reduced by 34% when compared with fish oil alone (P < 0.05). The plasma triacylglycerol fraction decreased further by 44% (P < 0.001). Other beneficial effects observed included a 30% decline in the fatty acid fraction (P < 0.002) by end of the treatment period. Diabetic control was maintained during the 12-wk study. In conclusion, a high fiber intake may be beneficial in fish oil-treated diabetic patients.     

Influence of reduced glutathione infusion on glucose metabolism in patients with non-insulin-dependent diabetes mellitus

To evaluate the relationship between oxidative stress and glucose metabolism, insulin sensitivity and intraerythrocytic reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio were measured in 10 non-insulin-dependent diabetes mellitus (NIDDM) patients and 10 healthy subjects before and after the intravenous administration of GSH. In particular, after baseline insulin sensitivity was assessed by a 2-hour euglycemic hyperinsulinemic clamp, either glutathione (1.35 g x m2 x min(-1)) or placebo (saline) were infused over a period of 1 hour. The same protocol was repeated at a 1-week interval, in cross-over, according to a randomized, single-blind design. In healthy subjects, baseline intraerythrocytic GSH/GSSG ratio (P < .0005) and total glucose uptake (P < .005) were significantly higher than in NIDDM patients. In the same subjects, GSH infusion significantly increased total glucose uptake (from 37.1 +/- 6.7 micromol kg(-1) x min(-1) to 39.5 +/- 7.7 micromol x kg(-1) x min(-1), P < .05), whereas saline infusion was completely ineffective. In addition, the mean intraerythrocytic GSH/GSSG ratio significantly increased after GSH infusion (from 21.0 +/- 0.9 to 24.7 +/- 1.3, P < .05). Similar findings were found in diabetic patients, in whom GSH infusion significantly increased both total glucose uptake (from 25.3 +/- 9.0 micromol x kg(-1) x min(-1) to 31.4 +/- 10.0 micromol x kg(-1) x min(-1), P < .001) and intraerythrocytic GSH/GSSG ratio (from 14.8 +/- 4.1 to 21.7 +/- 6.7, P < .01). Pooling diabetic patients and controls, significant correlations were found between intraerythrocytic GSH/GSSG ratio and total glucose uptake (r = .425, P < .05), as well as between increments of the same variables after GSH infusion (r = .518, P < .05). In conclusion, our data support the hypothesis that abnormal intracellular GSH redox status plays an important role in reducing insulin sensitivity in NIDDM patients. Accordingly, intravenous GSH infusion significantly increased both intraerythrocytic GSH/GSSG ratio and total glucose uptake in the same patients.     

Alcohol tolerance in patients with non-insulin-dependent diabetes (type 2) treated orally with drugs--derivatives of sulphonylurea

The oral ethanol loading test (0.5 g per kg b.m. given as 40% solution) was carried out in 5 groups, each of 10 patients with non-insulin-dependent (type 2) diabetes before and after 10 days of treatment with one of the following sulphonylurea derivatives: tolbutamide 0.5 t.i.d., chlorpropamide 0.5 once daily morning, glibornuride 0.025 t.i.d, glibenclamide 0.005 t.i.d. and glipizide 0.005 t.i.d. The response to alcohol (facial flush, heart rate, blood pressure) were compared, and blood concentration of ethanol, acetaldehyde, pyruvate, lactate, carbonates as well as blood pH, pO2 and pCO2 were determined in fasting state and during 6 hours after alcohol ingestion. In all patients the family history of diabetes and the presence and degree of vascular complications were registered. Evident flushing phenomenon was observed in 6 patients treated with chlorpropamide, in 3 treated with tolbutamide, in 2 treated with glibenclamide, in one receiving glibornuride and in none treated with glipizide. All drugs caused a greater rise of blood ethanol and acetaldehyde levels in relation to the control tests, but the difference reached statistical significance only in the group receiving chlorpropamide. Moreover, patients (pooled) with positive thermographic response had also significantly higher blood levels of ethanol and acetaldehyde during the second test. The ratio of acetaldehyde to ethanol concentration in blood (mumol:mmol) was not significantly changed in any group indicating parallel impairment of both steps of ethanol metabolism. All studied drugs intensified to a similar degree the alcohol-induced hypoglycaemia, but had no significant effect on the decrease of blood pyruvate level neither on the increase of blood lactate level. They didn't change the post-alcohol decrease of blood bicarbonate and pH, and didn't modify the behaviour of partial gas pressure. There was also no difference between pooled groups of patients with positive and negative thermographic reaction with respect to family history of diabetes and frequency and intensity of vascular complications. It is concluded that in patients with non-insulin-dependent (type 2) diabetes the second generation sulphonylurea derivatives are associated with lower risk of alcohol intolerance in case of its incidental ingestion in small amounts. The hypothesis of association of positive thermographic reaction to alcohol during treatment with sulphonylurea derivatives with more frequent occurrence of diabetes in family members and lower tendency to vascular complications was not confirmed.     

Specific and scavenger low-density lipoprotein receptors involved in the disturbed lipid metabolism of patients with non-insulin-dependent diabetes mellitus are independent of obesity

Comparative studies were performed on monocyte-derived macrophages (MDMs), prepared by a 72-hour incubation of blood monocytes obtained from patients with non-insulin-dependent diabetes mellitus (NIDDM) and age-matched obese and non-obese controls. The MDMs, after a 72-hour culturing, expressed both specific and scavenger low-density lipoprotein (LDL) receptors on their surfaces. To study the binding capacity of both receptor types, [125I]LDL and [125I] acetylated LDL (acLDL) were applied to cells and the labeled ligands were then monitored to estimate the rate of intracellular degradations. The LDL-induced inhibition of endogenous cholesterol synthesis and the acLDL-triggered apolipoprotein (apo) E secretion were also studied, as the biological marker of receptor activation. The results indicate that the binding capacities of both specific and scavenger LDL receptors were not reduced in MDMs of diabetic patients. However, the intracellular degradation after LDL incorporation was decreased. The LDL-induced inhibition of cholesterol synthesis and the acLDL-transmitted apo E secretion were also found to be decreased in the MDMs of patients with NIDDM as compared with the obese and non-obese control groups. The NIDDM-induced impaired signal transduction of both specific and scavenger LDL receptors suggests an unclarified functional alteration of both receptor structures.     

Diabetes mellitus and lipid metabolism (author''s transl)

Fifteen infants with pneumonia caused by respiratory syncytial virus (RSV) and 19 infants with bronchiolitis caused by RSV were studied for the influence of homologous, circulating neutralizing antibody on the severity of their illness. All infants were under nine months of age. Although maternal neutralizing antibody did not prevent infection with RSV and illness, the severity of pneumonia caused by RSV was inversely related to the level of neutralizing antibody. The severity of bronchiolitis caused by RSV was unrelated to maternal antibody levels. Chest roentgenograms showed pneumonia to be slightly more severe than bronchiolitis. Neither the severity of illness nor the presence of maternal neutralizing antibody was related to the development of complement-fixing antibody.     

The course of kidney function in type 2 (non-insulin-dependent) diabetic patients with diabetic nephropathy

We evaluated the impact of some putative progression promoters on kidney function in albuminuric Type 2 (non-insulin-dependent) diabetic patients with biopsy-proven diabetic glomerulosclerosis. Twenty-six patients (1 female) with a mean age of 52 (standard error 2) years and a known mean duration of diabetes of 9 (1) years were followed-up prospectively for a mean of 5.2 (range 1.0-7.0) years. Twenty-one patients received antihypertensive treatment. During the observation period the glomerular filtration rate decreased from 83 (24-146) to 58 (2-145) ml.min-1 x 1.73 m-2 (mean (range)) (p < 0.001). The mean rate of decline in glomerular filtration rate was 5.7 (-3.5 to 22.0) ml/min per year. Albuminuria increased from 1.2 (0.3-7.2) to 2.3 (0.4-8.0) g/24 h (geometric mean (range)) (p < 0.001). Arterial blood pressure remained unchanged: 162/93 (SE 4/3) and 161/89 (4/2) mm Hg. Univariate analysis showed the rate of decline in glomerular filtration rate to correlate with systolic blood pressure (r = 0.71, p < 0.001), mean blood pressure (r = 0.56, p < 0.005), albuminuria (r = 0.58, p < 0.005) and the initial glomerular filtration rate (r = -0.49, p < 0.02). The rate of decline in glomerular filtration rate did not correlate significantly with dietary protein intake, total cholesterol, high-density lipoprotein cholesterol or HbA1c. Three patients died from uraemia and four patients died from cardiovascular disease. Two patients required renal replacement therapy at the end of the observation period. Our prospective observational study revealed that one-fifth of the patients developed end-stage renal failure during the 5-year observation period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Daily energy metabolism in patients with type 1 diabetes mellitus

The availability of markers for the 17p11.2 region has enabled the diagnosis of Smith-Magenis syndrome (SMS) by fluorescence in situ hybridization (FISH). SMS is typically associated with a discernible deletion of band 17p11.2 upon cytogenetic analysis at a resolution of 400-550 bands. We present a case that illustrates the importance of using FISH to confirm a cytogenetic diagnosis of del(17)(p11.2). Four independent cytogenetic analyses were performed with different conclusions. Results of low resolution analyses of amniocytes and peripheral blood lymphocytes were apparently normal, while high resolution analyses of peripheral blood samples in two laboratories indicated mosaicism for del(17)(p11.2). FISH clearly demonstrated a 17p deletion on one chromosome of all peripheral blood cells analyzed and ruled out mosaicism unambiguously. The deletion was undetectable by flow cytometric quantitation of chromosomal DNA content, suggesting that it is less than 2 Mb. We conclude that FISH should be used to detect the SMS deletion when routine chromosome analysis fails to detect it and to verify mosaicism.     

The association of non-insulin-dependent diabetes mellitus and cognitive function in an older cohort

This is the first demonstration of the use of accelerator mass spectrometry (AMS) as a tool for the measurement of 3H with attomole (10(-18) mol) sensitivity in a biological study. AMS is an analytical technique for quantifying rare isotopes with high sensitivity and precision and has been most commonly used to measure 14C in both the geosciences and more recently in biomedical research. AMS measurement of serially diluted samples containing a 3H-labeled tracer showed a strong correlation with liquid scintillation counting. The mean coefficient of variation of 3H AMS based upon the analysis of separately prepared aliquots of these samples was 12%. The sensitivity for 3H detection in tissue, protein, and DNA was approximately 2-4 amol/mg of sample. This high sensitivity is comparable to detection limits for 14C-labeled carcinogens using 14C AMS and demonstrates the feasibility of 3H AMS for biomedical studies. One application of this technique is in low-dose, dual-isotope studies in conjunction with 14C AMS. We measured the levels of 3H-labeled 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 14C-labeled 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) in rat liver tissue and bound to liver DNA and protein 4.5 h following acute administration of individual or coadministered doses in the range of 4-5100 pmol/kg of body weight. Levels of PhIP and MeIQx in whole tissue and bound to liver protein were dose-dependent. MeIQx-protein and -DNA adduct levels were higher than PhIP adduct levels, which is consistent with their respective carcinogenicity in this organ. Coadministration of PhIP and MeIQx did not demonstrate any measurable synergistic effects compared to administration of these compounds individually. These studies demonstrate the application of AMS for the low-level detection of 3H in small biological samples and for its use in conjunction with 14C AMS for dual-labeling studies.     

The genetics of human noninsulin-dependent (type 2) diabetes mellitus

Familial aggregation and concordance in monozygotic and dizygotic twins argue strongly for a genetic etiology to noninsulin-dependent diabetes (NIDDM). Nonetheless, studies of pathways implicated by the known physiology have failed to identify gene defects that can explain the genetic susceptibility. In contrast, studies of early onset dominant diabetes have revealed three major loci resulting in diminished insulin secretion. Recently, studies have taken a new approach to map the genes causing typical NIDDM using large numbers of families or sibling pairs. The first reports of these studies have suggested possible loci on chromosomes 1, 2 and 12, but no report has been confirmed. Other studies have examined the quantitative defects that may be precursors of clinical NIDDM such as hyperinsulinemia, hyperglycemia, insulin response to glucose and obesity. These studies have suggested additional loci that may contribute to NIDDM susceptibility, but the genes responsible for most of these loci remain unknown. Studies of NIDDM susceptibility and the role of obesity genes in that susceptibility have entered an exciting new phase, but the challenges of complex disease genetics in humans will have to be conquered to translate this research into preventive or therapeutic benefits.