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MB Sample ID: SA024594

Local Sample ID:ms5361-25
Subject ID:SU000504
Subject Type:Animal
Subject Species:Homo sapiens
Taxonomy ID:9606
Species Group:Human

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Treatment:

Treatment ID:TR000518
Treatment Summary:Before and after 16 weeks of CR or CON, two outpatient visits and one inpatient visit were scheduled. Before the outpatient visits, participants were instructed to fast overnight from 10:00 p.m. the evening before and to avoid strenuous exercise for 24 h preceding the visits. One outpatient visit consisted of an MRI to measure subcutaneous and visceral fat distribution and magnetic resonance spectroscopy to measure skeletal muscle oxidative capacity (25). The second outpatient visit was for measurements of resting energy expenditure (REE) for the calculation of a weight-maintenance diet (Parvo Medics TrueOne 2400 Canopy system), DEXA scan (Lunar DPX-L; Lunar Radiation, Madison, WI), and VO2peak test on a bicycle ergometer (Fig. 1). Participants were admitted to the Clinical Research Unit (CRU) on the evening of the fifth day of the weight-maintaining diet provided by the CRU metabolic kitchen (Supplementary Fig. 1). The weight-maintenance meals (diet composition: 20% protein, 30% fat, 50% carbohydrate) were monitored daily to ensure that the correct calorie level was achieved. Upon admission to the CRU, no calories were consumed after 2100 h to achieve a 10-h fast before the two-stage insulin euglycemic pancreatic clamp the following morning, as previously published (26), with modifications as follows: the following morning at 0400 h, a primed [6,62H2]glucose bolus (6 mg ⋅ kg fat-free mass[FFM]−1) was administered, followed by a 9-h continuous infusion of [6,62H2]glucose (started at 4 mg ⋅ kgFFM−1 ⋅ h−1 then titrated downward over the infusion time period to match anticipated changes in endogenous glucose production [EGP]). At 0600 h, gas exchange was measured by indirect calorimetry for 30 min for REE determination. Then at 0700 h, glucagon (0.001 μg ⋅ kgFFM−1 ⋅ min−1), somatostatin (0.093 μg ⋅ kgFFM−1 ⋅ min−1), and growth hormone (0.0047 μg ⋅ kgFFM−1 ⋅ min−1) were infused for 6 h. Insulin was infused from 0700 to 1000 h at 0.62 mU ⋅ kgFFM−1 ⋅ min−1 and then from 1000 to 1300 h at 2.3 mU ⋅ kgFFM−1 ⋅ min−1. A 40% dextrose with 2% enrichment of [6,62H2]glucose was infused as needed to maintain blood glucose above 4.7 mmol/L from 0700 to 1000 h and then between 4.7 and 5.3 mmol/L from 1000 to 1300 h.
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