Basal activation of p70S6K results in adipose-specific insulin resistance in protein-tyrosine phosphatase 1B -/- mice.

Although protein-tyrosine phosphatase 1B (PTP-1B) is a negative regulator of insulin action, adipose tissue from PTP-1B-/- mice does not show enhanced insulin-stimulated insulin receptor phosphorylation. Investigation of glucose uptake in isolated adipocytes revealed that the adipocytes from PTP-1B-/- mice have a significantly attenuated insulin response as compared with PTP-1B+/+ adipocytes. This insulin resistance manifests in PTP-1B-/- animals older than 16 weeks of age and could be partially rescued by adenoviral expression of PTP-1B in null adipocytes.

Percent relative cumulative frequency analysis in indirect calorimetry: application to studies of transgenic mice.

Indirect calorimetry is commonly used in research and clinical settings to assess characteristics of energy expenditure. Respiration chambers in indirect calorimetry allow measurements over long periods of time (e.g.

Exercise in a pill: feasibility of energy expenditure targets.

The possibility of developing a pill to increase energy expenditure is explored by examining the metabolic processes involved. Such a pill should be targeted at organ systems involved in facultative thermogenesis. In rodents, these are brown adipose tissue (BAT) and skeletal muscle.

Brown adipose tissue: a factor to consider in symmetrical tracer uptake in the neck and upper chest region.

Increased symmetrical fluorine-18 fluorodeoxyglucose (FDG) uptake in the cervical and thoracic spine region is well known and has been attributed to muscular uptake. The purpose of this study was to re-evaluate this FDG uptake pattern by means of co-registered positron emission tomography (PET) and computed tomography (CT) imaging, which allowed exact localisation of this uptake. Between April and November 2001, 638 consecutive patients referred for PET/CT were imaged on an in-line PET/CT system (GEMS).