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Translocation Of The Glucose Transporter Glut4 In Cardiac Myocytes Of The Rat., Jan W. Slot, Hans J. Geuze, Sander Gigengack, David E. James, Gustav E. Lienhard

Dartmouth Scholarship

The insulin-regulated glucose transporter GLUT4 was immunolocalized in rat cardiac muscle under conditions of basal and stimulated glucose uptake, achieved by fasting and a combined exercise/insulin stimulus, respectively. In basal myocytes there was very little (less than 1%) GLUT4 in the different domains of the plasma membrane (sarcolemma, intercalated disk, and transverse tubular system). GLUT4 was localized in small tubulo-vesicular elements that occur predominantly near the sarcolemma and the transverse tubular system and in the trans-Golgi region. Upon stimulation approximately 42% of GLUT4 was found in the plasma membrane. Each domain of the plasma membrane contributed equally to this effect. …

Insulin Resistance Associated With Lower Rates Of Weight Gain In Pima Indians, Boyd A. Swinburn, Bulangu L. Nyomba, Mohammad F. Saad, Francesco Zurlo, Itamar Raz, William C. Knowler, Stephen Lillioja, Clifton Bogardus, Eric Ravussin

Graduate School of Medicine - Papers (Archive)

Insulin resistance is commonly associated with obesity and noninsulin-dependent diabetes. Whereas it predicts the development of diabetes, its effect on body weight change is unknown. We measured glucose disposal rates at submaximally- and maximally-stimulating insulin concentrations in 192 nondiabetic Pima Indians and followed their weight change over 3.5±1.8 y (mean±SD).

Results: (a) Insulin-resistant subjects gained less weight than insulin-sensitive subjects (3.1 vs. 7.6 kg, P < 0.0001). (b) The percent weight change per year correlated with glucose disposal at submaximally- (r = 0.19, P < 0.01) and maximallystimulating (r = 0.34, P < 0.0001) insulin concentrations independent of sex, age, initial weight, and 24-h energy expenditure; the correlations were stronger for glucose oxidation than for glucose storage. (c) Weight gain was associated with an increase in insulin resistance more than four times that predicted from the cross-sectional data.

We conclude that insulin resistance is associated with a reduced risk of weight gain in nondiabetic Pima Indians.

Racial Differences In The Relation Between Blood Pressure And Insulin Resistance, Mohammad F. Saad, Stephen Lillioja, B Nyomba, Castillo C, R Ferraro, M De Gregorio, E Ravussin, W C. Knowler, P H. Bennett, B Howard, C Bogardus

Graduate School of Medicine - Papers (Archive)

Background. Insulin resistance and the concomitant compensatory hyperinsulinemia have been implicated in the pathogenesis of hypertension. However, reports on the relation between insulin and blood pressure are inconsistent. This study was designed to investigate the possibility of racial differences in this relation. Methods. We studied 116 Pima Indians, 53 whites, and 42 blacks who were normotensive and did not have diabetes; the groups were comparable with respect to mean age (29, 30, and 32 years, respectively) and blood pressure (113/70, 111/68, and 113/68 mm Hg, respectively). Insulin resistance was determined by the euglycemic-hyperinsulinemic clamp technique during low-dose (40 Mu per …