Fedt og Sukkerstofskiftet Under Faste Hos Patienter Med Lav Muskelmasse.

Design. This is a prospective case-control study investigating fat and glucose metabolism in patients with low muscle mass during prolonged fasting, comparing results to those found in healthy controls.

Setting. All children were admitted to the Department of Pediatrics and Adolescents medicine, Rigshospitalet, and all adult subjects were admitted to the Department of Neurology, Rigshospitalet at 4 pm for a 24-hour fasting period.

Protocol. The protocol consisted of two visits. A pre-experimental visit and a study visit.

Pre-experimental visit. Total muscle mass presented as lean body mass (LBM) was measured by DEXA scan. Furthermore, pre-experimental preparations included that all subjects were instructed to follow national nutritional recommendations with a healthy diet consisting of less than 30% fat, low fat protein, long chain carbohydrates and minimize sugar intake three days before the study.

Study visit. Patients were admitted to the hospital at 16:00 hours for IV catheter placement and a standardized evening meal at 17:00. Two venous catheters were inserted, one in the cubital vein (for stable-isotope infusion) and one in the distal cephalic vein (for blood sampling). A heating pad, covering the hand and distal forearm, ensured shunting of arterial blood to the veins in order to obtain arterialized blood. A primed, constant rate infusion of [U-13C]-palmitate (0.0026 mg kg-1 min-1, primed by a 0.085 mg kg-1 NaH13CO3 bolus) and [D2]-glucose (0.0728 mg kg-1 min-1, primed by a 3.203 mg kg-1 D2- glucose bolus) was delivered by a Gemini PC2 pump (IMED, San Diego, CA). Preparation of tracers and tracer calculations were performed as described.