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R S Surwit

Publications and source records attributed to R S Surwit.

At least 37 records · Page 2Linked to original sources
PubMed1996

The role of motor activity in diet-induced obesity in C57BL/6J mice.

Previous research in our laboratory has demonstrated that the C57BL/6J (B/6J) mouse has a predisposition to develop severe obesity if placed on a high-fat diet. In the present study we assessed the role of physical activity in this phenomenon. Obesity-prone B/6J and obesity-resistant A/J mice were placed on one of four diets; high fat/high sucrose, high fat/low sucrose, low fat/high sucrose, and low fat/low sucrose. After 4 months, all animals on the high-fat diets had gained more weight than animals on the low-fat diets, and this phenomenon was greatly exaggerated in B/6J mice. Despite the fact that B/6J mice gained more weight than A/J mice on high-fat diets without consuming more calories, spontaneous motor activity was elevated in B/6J mice compared to A/J mice. There was no effect of the diets on activity either within or across strains. These data suggest that predisposition to diet-induced obesity is not explainable by reduced levels of physical activity.

Animals↗
PubMed1996

L-glutamine supplementation of a high fat diet reduces body weight and attenuates hyperglycemia and hyperinsulinemia in C57BL/6J mice.

C57BL/6J (B/6J) mice are genetically predisposed to become overweight and develop hyperglycemia if raised on a high fat diet. The purpose of the present study was to explore the effect of dietary supplementation of L-glutamine (Gln), an inhibitor of fatty acid oxidation, on the development of hyperglycemia and excessive weight gain. Groups of 10 age- and weight-matched male B/6J mice were raised on one of four diets: 1) a low fat, low sucrose (LL), studied separately, 2) a high fat, low sucrose (HL) diet alone, 3) high fat, low sucrose supplemented with L-glutamine (HL+Gln) and 4) high fat, low sucrose supplemented with L-alanine (HL+Ala). Energy intake, body weight, plasma glucose and insulin concentrations were monitored over time. We found no difference in energy intake per unit body weight between any groups after the first 2 wk of feeding. However, the mean +/- SEM for body weight (27.1 +/- 0.6 g) of the LL group measured at 16 wk was lower (P < 0.05) than that of the HL group at 37.9 +/- 1.9 g. Also, after 5.5 mo, the mean +/- SEM for plasma glucose and insulin concentrations in the LL group of mice were 6.9 +/- 0.4 mmol/l and 146 +/- 30 pmol/l, which were lower (P < 0.05) than those in the HL group at 10.1 +/- 0.9 mmol/l and 438 +/- 84 pmol/l, respectively. Although both amino acids caused a 10% reduction (P < 0.05) in body weight compared with HL feeding at wk 16, only Gln supplementation resulted in persistent reductions in both plasma glucose and insulin concentrations over 5.5 mo. In another experiment, when Gln was added to the high fat (HL) diet of heavy hyperglycemic animals for 2 mo, body weight gain, hyperglycemia and hyperinsulinemia were attenuated. In conclusion, supplementing glutamine to a high fat diet reduces body weight and attenuated hyperglycemia and hyperinsulinemia in B/6J mice.

Animals↗
PubMed1995

Glipizide stimulates sympathetic outflow in diabetes-prone mice.

The purpose of the present study was to determine if the oral hypoglycemic agent glipizide influenced sympathetic outflow in diabetes-prone mice. C57BL/6 (diabetes-prone) and diabetes-resistant (A/J) were treated with saline or glipizide, and sympathetic outflow determined by the fall in organ norepinephrine content after synthesis inhibition with alpha-methyl-para-tyrosine. Sympathetic outflow to the liver and pancreas were slower in Bl/6 mice than in control A/J. Glipizide increased sympathetic outflow to the pancreas in both strains of mice, but did not influence outflow to other organs significantly. The results of this study suggest that glipizide can influence central glucoregulatory mechanisms after peripheral administration.

Animals↗
PubMed1995

Differential effects of fat and sucrose on the development of obesity and diabetes in C57BL/6J and A/J mice.

We have previously demonstrated that the C57BL/6J (B/6J) mouse will develop severe obesity, hyperglycemia, and hyperinsulinemia if weaned onto a high-fat, high-sucrose (HH) diet. In the present study, we compared the effects of fat and sucrose separately and in combination on diabetes- and obesity-prone B/6J and diabetes- and obesity-resistant A/J mice. After 4 months, the feed efficiency ([FE] weight gained divided by calories consumed) did not differ across diets in A/J mice, but B/6J mice showed a significantly increased FE for fat. That is, B/6J mice gained more weight on high-fat diets without consuming more calories than A/J mice. The increase in FE was related to adipocyte hyperplasia in B/6J mice on high-fat diets. Fat-induced obesity in B/6J mice was unrelated to adrenal cortical activity. In the absence of fat, sucrose produced a decreased in FE in both strains. Animals fed a low-fat, high-sucrose (LH) diet were actually leaner than animals fed a high-complex-carbohydrate diet. Fat was also found to be the critical stimulus for hyperglycemia and hyperinsulinemia in B/6J mice. In the absence of fat, sucrose had no effect on plasma glucose or insulin. These data clearly show that across these two strains of mice, genetic differences in the metabolic response to fat are more important in the development of obesity and diabetes than the increased caloric content of a high-fat diet.

Adipose Tissue↗
PubMed1995

Tissue-specific alterations in G protein expression in genetic versus diet-induced models of non-insulin-dependent diabetes mellitus in the mouse.

Various tissues were obtained from the well-characterized genetic model (C57BL/6J-ob/ob) of non-insulin-dependent diabetes mellitus (NIDDM) and from a diet-induced model of NIDDM produced in the same genetic background (C57BL/6J). The objectives were to determine whether the previously observed changes in guanine nucleotide-binding regulatory protein (G protein) expression in adipose tissue from ob/ob mice were mirrored by concomitant changes in other tissues, and whether NIDDM of a different etiology would share similar alterations in G protein expression. Plasma membranes from adipocytes, brain, heart, liver, and testes were probed with alpha-subunit-specific antisera, and the level of G protein expression in each model was compared with that in its lean littermate control. Adipose, heart, and liver cell membranes from ob/ob mice contained significantly less alpha-subunit of stimulatory G protein (Gs alpha) than those from their lean littermates. As compared with the lean littermates, heart alpha-subunit-2 of inhibitory G protein (Gi alpha-2), liver Gi alpha-3, and adipocyte G1 alpha-1 and Gi alpha-3 were also reduced in ob/ob mice. In contrast, Gi alpha-2 and Go alpha were increased over lean-control levels in brain tissue from ob/ob mice, whereas Gs alpha was unchanged. G protein expression in the testes did not differ between lean and ob/ob mice. In the diet-induced model of NIDDM, Gs alpha expression in the liver was twofold greater in obese/diabetic mice as compared with lean controls. However, G protein expression in all other tissues examined did not differ between obese/diabetic animals and lean littermates.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1995

Impaired second phase insulin response of diabetes-prone C57BL/6J mouse islets.

The C57BL/6J mouse develops obesity and diabetes in response to a high-fat, high-simple carbohydrate diet. To determine the dynamics of glucose-induced insulin release in this animal model of NIDDM, we studied the acute insulin response to glucose of perifused islets in C57BL/6J (diabetes-prone) and A/J (diabetes-resistant) mice fed a normal control diet and of others fed a diabetogenic diet. The insulin response of normal C57BL/6J islets was almost monophasic, with a deficiency in the second phase during high glucose stimulation when compared to that of A/J control islets. The defect in C57BL/6J mice was exaggerated in animals fed a diabetogenic diet. It is suggested that a latent deficiency of second phase insulin release may contribute to the development of the diet-induced syndrome in this model.

Animals↗
PubMed1995

Defective glucose-stimulated insulin release from perifused islets of C57BL/6J mice.

Previous work has shown that the C57BL/6J (BL/6) mouse strain develops type 2 diabetes after being fed a high-fat, high-simple carbohydrate (HFHSC) diet. In contrast, the AJ mouse strain does not. The aim of the present study was to determine if differences in the insulin secretory characteristics of isolated perifused islets of these animals could help explain why the BL/6 mouse develops diet-induced diabetes. Insulin secretion was assessed as mean integrated area under the curve during 20 min of stimulation with 27.7 mM glucose or 5 mM lauric acid. We found that both glucose- and laurate-stimulated insulin secretions were significantly less in euglycemic BL/6 mice than in the euglycemic AJ mice. The defect in insulin response to glucose, but not laurate, in islets from the BL/6 mouse was exacerbated when the animals were fed the HFHSC diet. These data suggest that the BL/6 mouse has a defective insulin response to glucose, which is exacerbated by a diabetogenic diet.

Animals↗
PubMed1994

Kegel exercises and childhood incontinence: a new role for an old treatment.

Kegel exercises were used to treat urinary incontinence in 79 children. An average of less than 2 hours of professional time was required. Incontinence was eliminated in 60% of the patients; children who had both day and night wetting tended to show simultaneous improvements in both problems. Research is needed to test the hypothesis that Kegel exercises eliminate involuntary contractions of the detrusor muscle.

Adolescent↗
PubMed1994

Glycogen synthase: a putative locus for diet-induced hyperglycemia.

Inbred mouse strains fed a diabetogenic diet have different propensities to develop features analogous to type 2 diabetes mellitus. To define chromosomal locations that control these characteristics, recombinant inbred strains from diabetes-prone C57BL/6J (B/6J) and diabetes-resistant A/J strains were studied. Insulin levels and hyperglycemia correlated with two different regions of mouse chromosome 7 (two point LOD scores > 3.0). For insulin levels, 15 of 16 recombinant inbred strains were concordant with a region that contains the tubby mutation that results in hyperinsulinemia. For hyperglycemia, 19 of 23 strains were concordant with the D7Mit25 marker and 20 of 23 strains with the Gpi-1 locus on proximal mouse chromosome 7. Using more stringent criteria for hyperglycemia, 10 of 11 strains characterized as A/J or B/6J like were concordant with D7Mit25. This putative susceptibility locus is consistent with that of the glycogen synthase gene (Gys) recently suggested as a candidate locus by analyses of type 2 diabetes patients. Fractional glycogen synthase activity in isolated muscle was significantly lower in normal B/6J diabetic-prone mice compared with normal diabetic-resistant A/J mice, a finding similar to that reported in relatives of human patients with type 2 diabetes. These data, taken together, raise the possibility that defects in the Gys gene may in part be responsible for the propensity to develop type 2 diabetes.

Animals↗
PubMed1994

Glycemic response to stress is altered in euglycemic Pima Indians.

The aim of this work was to study the effects of a computer-driven mental arithmetic task on blood glucose in a group of four male and four female euglycemic Caucasians and a group of seven male and six female euglycemic Pima Indians. Approximately 60% of euglycemic Pima Indian Native Americans eventually develop type 2 diabetes, while only 5% of Caucasians develop the disease. All subjects had normal glucose tolerance. Subjects were given a standard breakfast; 2 h later, they were given a computerized mental arithmetic stress test for 10 min. Before, during and after the test, several variables were analyzed, including serum concentrations of glucose, insulin, glucagon and plasma cortisol and catecholamines. Heart rate, systolic and diastolic blood pressure and all the stress hormones increased during stress and decreased during recovery in all subjects. Blood glucose consistently declined one hour after the meal in all subjects. However, while it continued to decline following stress in seven out of eight Caucasian subjects, it consistently increased during and following stress in 10 out of 13 Pima Indians. Fasting serum glucose in Pima Indians and Caucasians was respectively 5.07 + 0.08 mM and 5.04 + 0.09 mM. Two-hour post-prandial values were 5.63 + 0.22 mM and 5.48 + 0.19 mM respectively, whereas post-stress values were 6.15 + 0.19 mM for Pima Indians and 5.22 + 0.20 mM for Caucasians. Both serum glucose means following stress (t = 3.1, P < 0.005) and the direction of change in serum glucose in response to mental arithmetic (chi 2 = 8.2, P < 0.01) clearly differentiated Pimas from Caucasians.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Relaxation training for NIDDM. Predicting who may benefit.

OBJECTIVE: To examine the benefits of relaxation training for patients with NIDDM and to investigate individual differences that could predict a positive response to relaxation training. RESEARCH DESIGN AND METHODS: Thirty-eight subjects with NIDDM were treated with intensive conventional diabetes therapy after an initial metabolic evaluation and psychological and pharmacological testing. Half were assigned to also receive biofeedback-assisted relaxation training. Treatment effects on GHb levels and glucose tolerance were evaluated after 8 wk. RESULTS: Subjects demonstrated significant improvements in GHb level, but not in glucose tolerance, after 8 wk of intensive conventional treatment. These improvements persisted throughout the follow-up period. However, the group provided with relaxation training did not experience greater improvements on either measure than the group given conventional diabetes treatment only. Within the group that received relaxation training, correlations occurred between the improvements in glucose tolerance after treatment and individual differences in trait anxiety and in the effect of alprazolam on glucose tolerance. Differences in the effects of EPI on glucose tolerance and personality measures of neuroticism and perceived locus of control also appeared to be related to improvements in glucose tolerance after training. CONCLUSIONS: Relaxation training did not confer added benefit over and above that provided by conventional diabetes treatment for patients with NIDDM. Additional research is needed to determine whether the administration of relaxation training to selected patients, especially those who are most responsive to stress, would provide benefits for glucose control that are not achieved by conventional treatment.

Analysis of Variance↗
PubMed1992

Stress and diabetes mellitus.

Stress is a potential contributor to chronic hyperglycemia in diabetes. Stress has long been shown to have major effects on metabolic activity. Energy mobilization is a primary result of the fight or flight response. Stress stimulates the release of various hormones, which can result in elevated blood glucose levels. Although this is of adaptive importance in a healthy organism, in diabetes, as a result of the relative or absolute lack of insulin, stress-induced increases in glucose cannot be metabolized properly. Furthermore, regulation of these stress hormones may be abnormal in diabetes. However, evidence characterizing the effects of stress in type I diabetes is contradictory. Although some retrospective human studies have suggested that stress can precipitate type I diabetes, animal studies have shown that stressors of various kinds can precipitate--or prevent--various experimental models of the disease. Human studies have shown that stress can stimulate hyperglycemia, hypoglycemia, or have no affect at all on glycemic status in established diabetes. Much of this confusion may be attributable to the presence of autonomic neuropathy, common in type I diabetes. In contrast, more consistent evidence supports the role of stress in type II diabetes. Although human studies on the role of stress in the onset and course of type II diabetes are few, a large body of animal study supports the notion that stress reliably produces hyperglycemia in this form of the disease. Furthermore, there is mounting evidence of autonomic contributions to the pathophysiology of this condition in both animals and humans.

Animals↗
PubMed1991

Control of expression of insulin resistance and hyperglycemia by different genetic factors in diabetic C57BL/6J mice.

The inheritance of the tendency to develop diet-induced non-insulin-dependent (type II) diabetes was analyzed in crosses between diabetes-prone C57BL/6J (BL/6) mice and diabetes-resistant A/J mice. The effects of a diabetogenic diet on blood glucose and insulin levels, insulin sensitivity, and weight were evaluated in F1 and both (BL/6 X A/J) F1 X BL/6 and (BL/6 X A/J) F1 X A/J backcross mice. These results suggest that diet-induced hyperglycemia is largely determined by a recessive gene and diet-induced insulin resistance by a dominant gene. Analyses of both backcrosses indicated that insulin sensitivity and blood glucose levels were unrelated, suggesting that they are controlled by different genetic factors. This conclusion was supported by data from nine recombinant inbred BXA strains in which no correlation was observed between these variables. Furthermore, insulin sensitivity and body weight correlated differently in the two backcross groups, suggesting that insulin resistance is not simply a function of obesity. The number of genes that predominantly influence diabetic traits was estimated by comparing the variance observed in (BL/6 X A/J) F1 X BL/6 backcross mice with that observed in parental mice. The data suggest that relatively few genes predominantly affect the diabetic phenotype in this murine model.

Animals↗
PubMed1989

Differential glycemic effects of morphine in diabetic and normal mice.

C57BL/6J ob/ob mice, C57BL/6J+/? lean mice and A/J mice were given injections of 10 mg/kg of morphine or an equal volume of saline, and then blood was sampled by retroorbital sinus puncture. In addition, animals from each strain were exposed to a brief experimental stress ten minutes after the administration of morphine or saline. While morphine produced significant increases in serum glucose in albino mice, morphine lowered blood insulin in both C57BL/6J ob/ob and C57BL/6J+/? mice. Morphine significantly lowered blood insulin in A/J mice, but effects in C57BL/6J mice were not significant. In contrast, morphine attenuated blood glucose and insulin during stress in C57BL/6J ob/ob but did not significantly affect either glucose or insulin during stress in lean C57BL/6J or A/J mice. These results are interpreted in the light of other data suggesting that endogenous opiates modulate the effects of sympathetic nervous system activity in type II diabetes.

Animals↗