Effect of weight changes on serum insulin response in subjects with normal oral glucose tolerance

Analysis and a long-term follow up of ketosis-onset Japanese NIDDM patients

It has been reported that excessive intake of sugar-containing soft drinks results in diabetic ketoacidosis (DKA) or ketosis (DK) in obese patients with non-insulin dependent diabetes mellitus (NIDDM). We describe the clinical characteristics and results of long-term follow-up for 24 newly-diagnosed patients with acute-onset NIDDM presenting with DKA or DK. A history of excessive intake of sugar-containing soft drinks was found in 19 (Group A); serious non-diabetic illnesses were found in 5 (Group B). The range of patient ages in Group A was 16 to 57 years while all patients in Group B were 60 years or older. In Group A, no patient was positive for autoantibodies, specific HLAs for Japanese insulin dependent diabetes mellitus, or mutation of the beta-3-adrenergic receptor gene. The body mass indices (BMIs) at onset and admission and serum C-peptide immunoreactivities at admission and discharge were significantly higher in patients in Group A than in patients Group B. In conclusion, we reconfirmed that excessive intake of sugar-containing soft drinks is one of the contributing factors in DKA or DK-onset NIDDM patients. We found no autoimmune mechanism involved in the pathogenesis and that a polymorphism in the beta-3-adrenergic receptor gene could be associated with the development of soft-drink ketosis.

Masking of diabetic phenotype on a low-energy diet despite persistence of impaired insulin response

Type 2 diabetes has been postulated to be a "thrifty genotype" that aids fuel conservation; to investigate this hypothesis, type 2 diabetic and nondiabetic subjects, normal weight and obese, were studied after both 6 days on a 700-calorie diet and 6 days on a 2,800-calorie diet. On 2,800 calories per day, the median basal plasma glucose was raised in diabetics compared with nondiabetic subjects (median, 5.5 and 4.5 mmol/L, respectively; P = .003), but on the low-energy diet there was no difference (4.1 and 3.7 mmol/L, respectively; P greater than .05). Basal plasma insulin levels were similar in the diabetic and nondiabetic subjects and were twofold to threefold higher on the high- than low-energy diet in both diabetic (median, 7.8 and 3.1 mU/L on high- and low-energy diets, respectively; P = .007) and nondiabetic subjects (6.8 and 2.6 mU/L, respectively; P = .005). Similarly, the postprandial insulin concentrations increased to the same degree on the high- compared with the low-energy diet in diabetic (median postprandial increment, 14.9 and 3.4 mU/L; P = .005) and nondiabetic patients (9.5 and 3.0 mU/L; P = .005) and the beta cells in type 2 diabetes appeared to modulate normally to different calorie intakes. On both diets, the diabetic subjects had an impaired first-phase insulin response to an intravenous glucose load compared with nondiabetic subjects (high-energy diet median first-phase increment, 4.3 and 21.2 mU/L in diabetic and nondiabetic subjects, P = .0007; low-energy diet, 4.0 and 20.4 mU/L, respectively, P = .003).(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocyte count and hemoglobin levels in diabetic women

Fasting blood glucose, erythrocyte counts hemoglobin levels of 131 Libyan diabetic women of Tripoli , Libya were determined. The respective mean values were 223 +/- 7 mg X dl-1, 4.97 +/- 0.034 X 10(6) X mm-3 and 14.4 +/- 0.127 g X dl-1. Sixty-five percent of these diabetic women were obese. The highest percent of diabetics belong to the age group 46-55 years. The increase in prevalence of diabetes correlates with an increase in obesity. A significant positive correlation was found between body surface area and fasting blood glucose levels (r = 0.65; P less than 0.001). Elevated levels of erythrocyte count and hemoglobin were present in these diabetic patients. Significant correlations were found between body surface area and erythrocyte count, as well as between fasting blood glucose levels and erythrocyte count, indicating the effect of obesity and diabetes on erythrocyte numbers. A significant correlation was found between fasting blood glucose levels and hemoglobin (r = 0.35; P less than 0.001). The elevated levels of hemoglobin present in these patients may be the result of haemoconcentration due to polyuria, which is always present in poorly controlled diabetic patients. The results suggest a close relationship between diabetes and obesity. Regulation of body weight/surface area is an important factor in the control of diabetes. The elevated levels of erythrocyte count and hemoglobin reflect poor control of blood glucose levels in these diabetic patients.

Enhanced synthesis, storage, and secretion of insulin in pancreatic islets derived from obese subjects

Insulin biosynthesis, content, and secretion were investigated in islets derived from pancreas specimens of normal weight (100.4 +/- 1.1% of ideal body weight) and obese (137.2 +/- 5.9% of ideal weight) patients. The pancreatic islets from the obese subjects were characterized by a significantly enhanced glucose-induced insulin secretion and biosynthesis and by an insulin content that was nearly double when compared with islets from the nonobese subjects. The results support the hypothesis that an enhanced beta-cell reactivity significantly contributes to the insulin hyperresponse observed in the obese state.

Increase in insulin response after treatment of overt maturity-onset diabetes is independent of the mode of treatment

The changes in insulin response to a 100 g glucose tolerance test after treatment by diet, sulphonylurea and insulin were compared in non-ketotic diabetic patients who had fasting blood glucose concentrations higher than 160 mg/100 ml. Patients were selected so that their pre-treatment and post-treatment blood glucose levels were comparable between different treatment groups. Their insulin responses were poor initially but increased significantly when the diabetic state was improved by each treatment. The degree of improvement of insulin response was similar between different treatment groups, when their fasting blood glucose decreased below 140 mg/100 ml and the glucose tolerance curves were improved to a similar extent. Pre- and post-treatment sigma IRI values (sum of insulin values during glucose tolerance test, mean +/- SD) were 102 +/- 50 and 200 +/- 37 microU/ml in diet-treated group (n = 28), 90 +/- 40 and 195 +/- 53 microU/ml in sulphonylurea-treated group (n = 48), and 83 +/- 28 and 193 +/- 38 microU/ml in insulin-treated group (n = 13), respectively. The data suggest that the poor insulin response in overt diabetes results not only from an inherent insensitivity of B-cells to glucose but also from the metabolic derangement of diabetes. Poor insulin response and overtly diabetic metabolism seems to form a vicious cycle.

Effects of fat mass reduction by dieting and by lipectomy on carbohydrate metabolism in obese patients

The interrelation of enlarged body fat mass (BFM) with reduced carbohydrate tolerance and hyperinsulinemia was studied in obese subjects with chemical diabetes. These patients were subjected to lipectomy following weight loss induced by a low-calorie, low-carbohydrate diet. An improvement in glucose tolerance and in insulin sensitivity and a reduction in insulin release during OGTT was observed after a diet-induced BFM loss of 9.9 +/-1.2 kg. Subsequent surgical reduction of BFM by 6.0 +/- 0.5 kg had no further effect upon carbohydrate tolerance, insulin release or insulin sensitivity though a marked decrease in basal plasma FFA values was observed. These findings suggest that fat mass enlargement per se has no effect on blood glucose homeostasis after oral or i.v. loading. The improvement in carbohydrate tolerance and in insulin resistance usually observed following diet-induced loss of BFM seems to be due to the reduction in calorie and carbohydrate intake rather than to decrease of BFM.

Insulin response to glucose in hypermetabolic burn patients

Fifty-four intravenous glucose tolerance tests were performed in 12 normal individuals and 21 thermally injured patients. In the 17 hypermetabolic burn patients studied between the 6th and 16th days postinjury, fasting blood glucose was elevated (111 +/- 7 mg/100 ml, mean +/- SE compared to 85 +/- 3 in controls, P less than 0.001), but the instantaneous proportionality constant for glucose disappearance (k) was similar to that obtained in normal individuals (5.27 +/- 0.51, 100/min vs 4.01 +/- 0.58 in normals, NS). Fasting serum insulin concentrations were comparable in the 12 normals and 17 hypermetabolic burn patients (22 +/- 3muU/ml in normals vs 22 +/- 2), as was fasting insulin corrected for fasting glucose (24 +/- 3 in normals vs 21 +/- 3, NS), initial insulin response (0-10 min delta insulin, 58 +/- 13 in normals vs 67 +/- 10, NS) or total insulin response corrected per unit glycemic stimulus (insulinogenic index, 0.48 +/- 0.10 in normals vs 0.52 +/- 0.07, NS). With time following injury, the proportionality constant for glucose disappearance and insulin response decreased, and these alterations were related to the posttraumatic weight loss. In the 5 convalescent patients studied between the 37th and 90th days postinjury, glucose and insulin dynamics appeared similar to those observed in starved man. In these burn patients, hypermetabolism and negative nitrogen balance occurred in association with a normal insulin response to glucose. Increased hepatic gluconeogenesis appears to be characteristic of the catabolic response to this stress, directed by increased glucagon and catecholamines, not a decrease in fasting insulin or dampened insulin response.

Insulin secretion and glucose tolerance in adults with protein-calorie malnutrition

Glucose tolerance, insulin secretion, and responses to arginine infusion were studied in 17 adults with severe protein-calorie malnutrition (PCM) in Calcutta, India. Patients were selected for the severity of their malnutrition and for absence of other diseases. After 2-4 mo of refeeding there was complete clinical recovery, and control studies were performed. Glucose tolerance, as assessed by intravenous glucose-tolerance test (IVGTT), was reduced in PCM. Insulin response, both to glucose and to arginine infusion, was clearly reduced. The K value of the IVGTT correlated well with the ratio of mean to basal serum insulin during the first 40 min of the test. Basal serum insulin was nearly unchanged in PCM as compared with after recovery, although one patient studied serially showed a temporary drop in basal insulin during the first week of refeeding. In PCM, plasma amino acid levels failed to fall in response to arginine-induced insulin secretion as they did in the control studies. It appears that insulin secretory response is severely reduced in PCM and that a degree of insulin resistance in relation to body weight is present. These changes result in diminished glucose tolerance and probably in a reduced rate of tissue utilization of amino acids. Such alterations may be of adaptive significance in chronic PCM.

Effects of weight reduction on obesity. Studies of lipid and carbohydrate metabolism in normal and hyperlipoproteinemic subjects

Considerable controversy exists over the purported role of obesity in causing hyperglycemia, hyperlipemia, hyperinsulinemia, and insulin resistance; and the potential beneficial effects of weight reduction remain incompletely defined. Hypertriglyceridemia is one of the metabolic abnormalities proposed to accompany obesity, and in order to help explain the mechanisms leading to this abnormality we have proposed the following sequential hypothesis: insulin resistance --> hyperinsulinemia --> accelerated hepatic triglyceride(TG) production --> elevated plasma TG concentrations. To test this hypothesis and to gain insight into both the possible role of obesity in causing the above metabolic abnormalities and the potential benefit of weight reduction we studied the effects of weight loss on various aspects of carbohydrate and lipid metabolism in a group of 36 normal and hyperlipoproteinemic subjects. Only weak to absent correlations (r = 0.03 - 0.46) were noted between obesity and the metabolic variables measured. This points out that in our study group obesity cannot be the sole, or even the major, cause of these abnormalities in the first place. Further, we have observed marked decreases after weight reduction in fasting plasma TG (mean value: pre-weight reduction, 319 mg/100 ml; post-weight reduction, 180 mg/100 ml) and cholesterol (mean values: pre-weight reduction, 282 mg/100 ml; post-weight reduction, 223 mg/100 ml) levels, with a direct relationship between the magnitude of the fall in plasma lipid values and the height of the initial plasma TG level. We have also noted significant decreases after weight reduction in the insulin and glucose responses during the oral glucose tolerance test (37% decrease and 12% decrease, respectively). Insulin and glucose responses to liquid food before and after weight reduction were also measured and the overall post-weight reduction decrease in insulin response was 48% while the glucose response was relatively unchanged. In a subgroup of patients we studied both the degree of cellular insulin resistance and the rate of hepatic very low density (VLDL) TG production before and after weight reduction. These subjects demonstrated significant decreases after weight reduction in both degree of insulin resistance (33% decrease) and VLDL-TG production rates (40% decrease). Thus, weight reduction has lowered each of the antecedent variables (insulin resistance, hyperinsulinemia, and VLDL-TG production) that according to the above hypothesis lead to hypertriglyceridemia, and we believe the overall scheme is greatly strengthened. Furthermore, the consistent decreases in plasma TG and cholesterol levels seen in all subjects lead us to conclude that weight reduction is an important therapeutic modality for patients with endogenous hypertriglyceridemia.